Lord Justice Latham
On the 29th October 1997, these two appellants were convicted of conspiracy to evade the prohibition on the importation of Class A controlled drugs. Ronald Benn was sentenced to 9 years imprisonment, and Sylvia Benn to 6 years imprisonment. On the 10th December 1998, the full court refused both appellants’ renewed applications for leave to appeal against conviction which were based upon criticisms of the summing-up. They now appeal following the referral of their cases to this court by the Criminal Cases Review Commission (the Commission) under the Criminal Appeal Act 1995. The two grounds for referral to which we will refer in more detail later, were that on the one hand expert evidence had been obtained which threw doubt upon certain crucial findings relating to the presence of cocaine on items of theirs, and on the other that there were deficiencies in the judge’s summing-up relating to the effect of Sections 34 and 36 of the Criminal Justice and Public Order Act 1994 on the appellants’ refusals to answer questions in interview or provide an explanation of certain items of property when arrested.
THE PROSECUTION CASE
The case against the appellants was entirely circumstantial. Customs and Excise had noted that between July 1994 and November 1995 the appellants had made a total of thirteen trips from Hull to Rotterdam several being for very short periods, with various different return routes. On two occasions they had been stopped and on one occasion Mr. Benn had given an account of their movements which was untrue. On the 30th November 1995, they were stopped at Hull in Mr. Benn’s BMW motorcar. When questioned, he denied that he had any cash in the car. But when they searched the car, customs officers found a green holdall containing just short of £63,000 in bank notes. He gave an account as to where the money had come from, which the prosecution was able to establish was untrue.
The notes were examined and found to be significantly contaminated with cocaine. The main issue in this reference is the question of what inference or inferences can properly be drawn from the level of contamination found. But this evidence was only one part of the prosecution case.
As a result of the finding of cocaine on the notes, customs officers went to the appellant’s home on the 19th March 1996. Officers examined a safe and its contents, which consisted of bundles of money; both the inside of the safe and the money were contaminated with cocaine. A vacuum cleaner was examined. The dust in the dust bag was heavily contaminated with cocaine. Five suitcases were seized and found to be contaminated with cocaine. The BMW motorcar was examined; and contamination was found in the boot and in the passenger compartment.
In addition to this forensic evidence, an analysis of the appellants’ financial position showed that it improved markedly after each of the trips to the continent which the Customs and Excise were able to identify. In particular, after a journey in 1994, substantial sums of money were paid into their bank account, they discharged a number of credit card debts, paid off a large part of their mortgage, and some outstanding judgment debts, and paid for building work. They bought cars and enjoyed an expensive lifestyle which appeared to be financed by cash.
When interviewed on the 17th April 1996, they made no comment to the questions that they were asked. Each had a solicitor while interviewed. Before each interview the solicitor read a prepared statement stating that he had advised his client to make no comment firstly because there were so many documents that had been seized questions could not be answered adequately, and secondly, because the appellants had lost confidence in the integrity of the procedures regarding the seizure of the £63,000 and the application for its forfeiture.
THE DEFENCE CASE
The appellants accepted the forensic evidence as to the finding of cocaine contamination on the notes, but asserted that it was either innocent, in the sense that there was no reason to believe that the contamination on the cash was other than contamination which could have occurred during the lifetime of notes in ordinary circulation, or alternatively was the result of contamination by the handling by the customs officers or in the course of the forensic investigation. As far as the safe, the money in the safe, and the suitcases were concerned, that contamination was also either innocent or the result of contamination by those who were examining the items. As far as the dust in the vacuum cleaner was concerned, that was a cleaner which had been used at a hotel in which Mr. Benn had an interest in Blackpool, and must have been contaminated there. In turn, that could have contaminated the interior of the BMW. The five suitcases had been contaminated during the investigation.
As far as the money found with them in Hull was concerned, the appellants’ case was that was for the purchase of camper vans and consisted partly of his own cash and partly cash from three other individuals, including £12,000 from a Mr. Garner. Mr. Garner, however, did not support that account when he gave evidence. As far as the apparent transformation in the appellants’ lifestyle was concerned, they accepted that that was the result of the trips they made in 1994 and 1995 to the Continent, but said that the money came from the illicit sale of Sky Cards for Satellite Broadcasts and subsequently dealings in camper vans.
THE FORENSIC EVIDENCE AT TRIAL
The prosecution relied on the evidence of Dr Sleeman. He is a forensic chemist employed by Mass Spec Analytical Ltd, a company which has for many years specialised in chemical analysis using a method known as mass spectral analysis. The technique is extremely sensitive. It can detect one nanogram of a drug, that has been described in layman’s terms as being approximately one million times less that a single grain of sugar, but it cannot identify the precise quantity of the drug, although it can determine orders of magnitude. Scientific evidence for the appellants was given by Dr Young, also a chemist who was familiar with the technique used by MSA Ltd and who did not seek to dispute the validity of the technique or the reliability and accuracy of its findings, but merely the inferences which could or should be drawn from those findings.
Unfortunately, there is no transcript of the evidence of either Dr Sleeman or Dr Young. We have been provided, helpfully, with typed copies of the notes made by prosecution junior counsel, which do not pretend to be a complete or verbatim record. Otherwise, we are dependent upon the judges’ summing up and the comments which have been made on it by Dr Sleeman and counsel.
Dr Sleeman described to the jury the way in which mass spectral analysis was carried out, and in particular the method used to obtain the debris which was subject to this technique. As far as the notes found in the car were concerned, these were subjected to two investigations. The first was by what was described as batch analysis. This involved using a hand held vacuum cleaner with a specialised collection system, called a disposable brush-cartridge assembly (DBCA). The results obtained from each batch were then compared with a database obtained by another employee of MSA Ltd as a result of the examination of batches of used notes obtained from the Bank of England. The comparison showed the level of cocaine contamination on the batches of notes taken from the appellants was on average ten times higher than the cocaine contamination on the Bank of England notes, and that on some batches the level was 25 times that of the batches from the Bank of England. Individual notes were then subjected to a technique which vaporised any contaminants on the notes: The contamination levels were then compared with the levels on a data base taken from 3000 notes obtained by MSA Ltd from High Street Banks. The findings on this investigation confirmed the findings using the DBCA method.
Dr Sleeman’s evidence was that there was extremely heavy contamination, "very much higher than is typical" and that one possible explanation was that they had been in intimate contact with drugs. He accepted that there was the possibility of innocent contamination, although the checks that were made during the examination procedure suggested that it had not occurred. He was unable to rule out the possibility of contamination, but the level of contamination was not in his opinion capable of being explained by external or innocent contamination. Dr Young agreed that the level of cocaine contamination was significantly higher than notes from general circulation, but he was concerned that this might have happened purely by chance, alternatively it might have been the result of contamination during the investigation, in which case the results should be ignored.
In his summing, the judge correctly stated that Dr Sleeman and Dr Young were agreed as to the primary findings, and correctly reminded the jury that the evidence of both of them was to the effect that cocaine had a propensity to stick to bank notes, and that, at the time, it was thought that at least 80% of all bank notes in circulation would be contaminated with cocaine to some extent. He continued:
Now, members of the jury, both Dr Sleeman and Dr Young agree that the mere fact, or the mere finding from the testing of large amounts of contamination on notes cannot itself determine by whom or when or what circumstances that contamination came to be deposited and common sense would tell you that. But if you have got a very large sum of money, say the prosecution of sixty odd thousand pounds, the prime piece of evidence in this case and so much of it in different containers, plastic bags, as you know different wrappings and the contamination distributed throughout the bundles in large amounts as you have seen from your graphs and the documents put before you, then it is really going a lot further than simply notes taken at random and it points very strongly, says Dr Sleeman, to the person holding those notes being very close to the sources of contamination, and the sources of contamination are drug users and drug dealers.
The defence say, through Dr Young and Mr. Riordan (counsel for Mr. Benn) reminded you of this, but this is not good enough, there is another explanation possible, it is not the sole explanation. Well members of the jury, the analogy of the lottery, you may think, is apt. I tried to do the calculation during the course of the trial. I think Dr Young agreed it is more than a thousand million to one that we need but that somebody usually wins but then everybody else loses, but it is a thousand million to one.
Perhaps if you think of one note turning up in the volumes of notes in circulation, then you get notes of practically all of £62,000 worth of notes, 10, 20s, and so on then the coincidence is, the prosecution suggest, very striking indeed and whilst it is possible to find another explanation if you stretch your imagination a long way, that is not reason really reasonable; it is going too far, to stretching human incredulity far too far indeed. Members of the jury, Mr. Riordan used the phrase "consistent". It certainly is consistent with it coming from drug dealers. The question you have to address is are you sure it is not consistent with something else.
As far as the safe and its contents were concerned, both Dr Sleeman and Dr Young noted that the officer who obtained the samples had gone into the appellants’ home, together with other officers without protecting clothing. Samples taken from the protective suit which he ultimately put on before examining the safe and its contents showed traces of cocaine. These were only at about one tenth of the level found inside the safe; and was significantly less than the findings on the notes in the safe. The notes, however, showed levels of cocaine contamination which, although not as high as the notes found in the car, were nonetheless higher than the levels found on the Bank of England notes. Dr Sleeman, in his evidence, accepted that the method used to obtain the samples from the safe and its contents was flawed and that the findings should be viewed with some caution. He repeated this in cross-examination; and in re-examination said that although contamination was unlikely, he could not rule it out completely. Dr Young concurred. But it should be remembered that he took the view that if there was any risk of contamination, the results should be ignored.
In his summing-up, the judge correctly reminded the jury of the deficiencies in the examination and continued:
But members of the jury, you are entitled to use your own common sense as well and ask yourselves the question; "which is the more likely source of the contamination, the suit with the lower level or the inside of the safe the higher level?" you have to consider that one.
However, there is another question to be addressed. Mr. Unsworth had gone through the house, other people were in the house. Did other people have contamination on them or not? Is that a possibility? Is it a realistic possibility? Is it one that you feel you cannot exclude bearing in mind that the prosecution must prove the case. What all this comes down to is what Mr. Riordan was talking about when he talks about the integrity of the sampling and so you must look at all aspects of the case.
The money that came from that safe was independently, at least the sampling was tested, and that was shown to have levels not as high as the £62,000, you will remember, but still significantly higher than the levels of contamination to be found on money in general circulation.
You will also remember the criticism that advance of Mr. – I forgot the officers name – the officer whose notebook you have in your bundles suggested that he may have been adding something to his notes to suggest that the safe had been unlocked and the key retained safely by someone else then only then again opened for Mr. Unsworth. In other words you have to consider the question of whether it is possible for someone else by going into that safe had perhaps inadvertently or otherwise contaminated the contents of that safe.
As far as the contents of the bag of the vacuum cleaner found at the appellant’s home were concerned, there was no dispute. They were heavily contaminated, but not in nanograms; the calculation carried out by Dr Sleeman, which was not challenged by Dr Young, was that approximately 34 milligrams of cocaine was distributed among the contents. This level suggested that the vacuum cleaner "hoovered up cocaine which had been spilt on the floor". The issue for the jury was whether or not the appellants’ explanation might be true, namely that the vacuum cleaner had at one stage been used at the hotel in which Mr. Benn had an interest, so that the contents could have been the result of its use there.
In his summing-up, the judge said:
Then we come to the vacuum cleaner. Members of the jury, much in this case depends on the history of that vacuum cleaner. All that Customs did was to inform Mr. Hughes, seize the first vacuum cleaner bag that was there on the basis, well we always do that because we are looking, we don’t know what we are going to find. Having seized it and the contents were subject to analysis. I think something like, was it, 3.4 mmgs by extrapolation of cocaine were found distributed throughout the various bits of, in other words, inside the totality of the dust and in that vacuum cleaner. Now that is not random traces, that is not nanograms that is a quantifiable amount of cocaine.
The suggestion will be, how does cocaine get in somebody’s vacuum cleaner unless it has been used to vacuum something with cocaine on it like a carpet, may be something has been spilt. Members of the jury that is very cogent evidence. So very much depends on the history of the vacuum cleaner, where has it been, where has the cocaine come from, if it is a vacuum cleaner which is normally in the house, never been out of the house, it has quite serious import. So the history of the vacuum cleaner, how long has it been there, where has it been, becomes important.
The evidence relating to the suitcases, and the use made of it, is somewhat less clear. There is no doubt that traces of cocaine were found on all five suitcases. However, there is also no doubt that as far as two of the suitcases were concerned, controlled samples suggested that there may have been contamination either during the storage or investigation process; and it was accepted by the prosecution that their storage, which was in Manchester Airport, was not ideal and could have given rise to contamination. We have been told that the suitcases ultimately played no part in the prosecution’s case. However it is to be noted that Dr Sleeman answered some questions about the suitcases in examination in chief, and in one answer suggested that the most likely explanation in relation to one of the suitcases was that it had been used to carry cocaine. But he accepted the risk of contamination in his cross-examination; and Dr Young stated that that contamination should be ignored.
The judge in his summing up said:
As regards some of the suitcases, well those suitcases had in fact been stored in the warehouse but not in plastic bags. When they came out and the foil was tested in two of the cases the foil gave a reading, not a very high one but still gave a reading. What both Dr Sleeman and Dr Young said as regards those two suitcases "Well you have got the reading of the controlled of the foil which showed contamination, please ignore the finding about the suitcase because you can’t rely on it.
He did not mention the other suitcases at all in the course of the summing up.
Finally as far as the forensic evidence was concerned, there were findings of contamination in the BMW. As we have said, the examination of the BMW, using the DBCA collection method, showed the presence of cocaine in the boot, and in the passenger compartment. Dr Sleeman accepted that it was possible that the contamination could have been the result of the vacuum cleaner having been carried in the boot of the car, and that some contamination might have occurred if the vacuum cleaner was used to clean the inside of the car. He also accepted that contamination could have occurred when customs officers were examining the car and its contents in Hull. However, he did not consider that the levels of contamination were consistent with that. Dr Young confirmed the risk of contamination accepted by Dr Sleeman, and said, as he had before, that where there was the risk of such contamination, the results should be ignored.
The judge in the summing-up said:
Members of the jury, Dr Young in dealing with that said that if the vacuum cleaner had been brought back from Blackpool, depending on where it had been, if it was already itself contaminated, it is a possibility that contamination would have been transferred across into, for example, the boot of the car. As regards the other parts of the car, if the vacuum cleaner had been used, for example, to clean using its tools and the same tools had been used to vacuum the inside of the car, then there is a possibility of a transfer across.
No one has given any evidence to that vacuum being used to clean the car but evidence was given by Mr. Benn that he brought it back in the boot of his car. So that would be an explanation for the contamination in the boot of the car but not an explanation for contamination anywhere else. And this is what the defence say here is that that car was rummaged by customs officers and those customs officers were not wearing any protective suits in November when they rummaged that car and is it not a possibility if they, being customs officers, had come into contact with others with drug money with cocaine upon them or other things that had cocaine upon them when they searched the car could have transferred it from those persons to the car. That is a fact you will have to consider.
The judge further reminded the jury of the evidence that the BMW had only been in the possession of the appellants for about three months before November 1995 and that it, indeed, remained registered in the name of its previous owner, Mr. Jackson at the time of its seizure in March 1996.
THE DECISION OF THE COMMISSION
The Commission referred Mr. Benn’s conviction to this court on the 31st July 2002 solely on the basis of evidence that had been submitted by Mr. Bottomley who is a chemist employed by what is described as the Laboratory of the Government Chemist Ltd. This is a potentially misleading title as it is a private company, although a substantial proportion of its work is undoubtedly for Government Departments, and, from the information provided to us in Mr. Bottomley’s statement would appear to have some statutory role in certain areas. His report raised a number of concerns about the techniques used to obtain samples and about the machine used to test the resulting samples. He pointed to a considerable amount of documentation suggesting that significant doubts had been raised about the accuracy and reliability of the technique used by MSA Ltd, particular using the DBCA method for collecting samples which apparently showed a number of "false/positive" results. The Commission concluded that the risks of contamination disclosed by this material had not been known to the defence at the trial and had therefore not been subjected to evaluation during the course of the evidence.
Mr. Bottomley also raised concerns about the possibilities of innocent contamination having occurred to the notes during the course of their handling by Customs and Excise whilst they were being collected, stored and examined. He also raised issues as to the possibility of similar contamination of the samples from the safe, the cleaner bag, the suitcases and the car. Finally Mr. Bottomley raised concerns about the validity of the comparison between the level and the distribution of cocaine on the notes found in the car, and the level of distribution of drugs on the notes "in general circulation".
The Commission concluded that Mr. Bottomley had indeed raised issues in relation to possible innocent contamination of the items that had been examined which were new and which justified a reference even though the issue of contamination in general had been considered during the course of the trial. It considered that the issue as to the validity of the inference to be drawn from the level of cocaine on the notes found in the appellant’s possession and the databases which were used for his comparison by Dr Sleeman was a new issue which in itself would justify a reference to this court. It referred the cases on the basis that there was a real possibility that this court would admit his evidence under Section 23 of the Criminal Appeal Act 1968 and that there was a real possibility that the conviction would, as a result, not be upheld.
As we have already indicated, in the case of Mrs. Benn, the reference, which was on the 16th September 2002, was on the additional basis that there had been a misdirection by the judge in relation to the inferences which the jury would be entitled to draw from the appellant’s failure to answer questions, under Sections 34 and 36 of the Criminal Justice and Public Order Act 1994.
The grounds of appeal reiterated the issues raised by the Commission in its references, that is the doubts as to the validity of the methodology employed by MSA Ltd, the doubts as to the robustness of the findings because of the risks of innocent contamination, the use made of the results of examinations which were, or are now, accepted to be matters which should not have been put before the jury, and the validity of the inferences drawn from the comparison between contamination on the notes in question and those in the data bases. Both appellants submit that the judge misdirected the jury in relation to Sections 34 and 36. And, at the hearing, Mr. Blaxland QC, on behalf of Mr. Benn sought to raise as a ground of appeal the fact that the judge did not give to the jury any direction in his summing up as to their approach to their lies told by Mr. Benn. In support of their grounds of appeal in relation to the forensic matters, they sought leave under Section 23 of the Criminal Appeal Act 1968 to call Mr. Bottomley, Dr Evett, and Professor Laycock. The prosecution sought leave to call the evidence of Professor Monaghan, Dr Sleeman and Professor Brereton. We considered that it was expedient in the interest of justice to admit the evidence of all those witnesses, although for reasons which will become apparent, we did so in relation to Mr. Bottomley without enthusiasm. Each of the witnesses provided us with extensive written material, for which we were very grateful, and which constituted their evidence in chief; and each was cross-examined.
His first statement is dated the 24th January 2003, it contains an extended critique of the methodology used by MSA Ltd and a detailed examination of the circumstances which could have given rise to innocent contamination accounting for the traces of cocaine found by Dr Sleeman. His conclusions were set out in paragraph 22 as follows:
The detection limit for the identification of a compound using the mass spectrometry is of the order of a few thousand millionths of a gramme. It is possible to detect particles which are invisible to the naked eye.
It is not possible to say how a trace of a particular drug comes to be deposited on a certain item.
By using sensitive techniques such as mass spectrometry it is possible to detect traces of drugs in items many months or even years after they have originally been in contact with drug particles.
It is not possible to determine the origin of the traces of any controlled substance found on items such as a bank note and then compare it with any larger seizure of drugs found elsewhere.
It is possible for traces of drugs to be present on an item or motor vehicle without the owner of the item knowing about them.
Very careful precautions will be required in order to prevent the inadvertent contamination and/or cross-contamination of items during the transfer, secure storage and analysis of seized items.
If the reported results are to have any evidential value, then the possibility of accidental cross-contamination of the bank notes by Customs Officers or other people must be excluded.
From the evidence which I have seen in this case there does not seem to be any direct evidence to link Mr. & Mrs. Benn with the larger quantity of controlled drugs.
There is a possibility that the inadvertent use of a domestic vacuum cleaner may have resulted in the cocaine contamination found at Mr. & Mrs. Benn’s house and in their BMW motor car.
The cocaine found in the vacuum cleaner dust bag may well have originated somewhere other than at 153, Leander Drive.
The removal and seizure of the vacuum cleaner dust bag by Mr. Brian Hughes and its subsequent handling by the Exhibits Officer, Mr. Riley, may have resulted in other items handled by Mr. Riley becoming contaminated by dust and drug particles.
In my opinion the re-analysis of the bank notes by MSA Ltd using the relatively new "individual Bank Note Technique" after the bundles of notes had already been sampled by officers of HM Customs and Excise may have given the impression that the bank notes had a higher frequency of contamination as was in fact the case due to the redistribution of drug traces during the original handling and sampling.
The use of the hand held vacuum sampling system by officers of HM Customs and Excise may have resulted in drug particles being removed from articles sampled and subsequently being blown out of the vacuum and into the air thereby resulting in the contamination of other items.
In his second statement of the 13th June 2003, he raised the question of the validity of the comparison between the level of contamination on the notes in the appellant’s possession, and the notes in the data bases. His summary was as follows:
The number of cases undertaken by MSA Ltd prior to the Benn case was extremely limited. The Benn case was only the third case of this type undertaken by MSA.
The number of "background studies" carried out on bank notes from general circulation at the time of the Benn case was also limited and the only significant study related to 97 bundles of notes as detailed in Fletcher Burtons MSc Thesis dated October 1995.
The data contained in the Fletcher Burton MSc Thesis seems to indicate that different denominations of bank notes have different levels of cocaine contamination on them.
The data contained in the Fletcher Burton MSc Thesis also seems to indicate that there may be geographical differences in contamination levels found on bank notes taken from "general circulation" and notes collected from London may have different levels of cocaine contamination on them.
There is no definition of what constitutes "general circulation" bank notes and the history of bank notes taken from High Street banks and the cash collections centres is unknown.
The MSc Thesis also concedes that a larger study needs to be undertaken to further validate these findings and concludes that a detailed statistical study of the data may reveal further information.
This second report raises the issues upon which the main focus of the evidence before us was directed. He pointed out that the data base which was used as a comparator with the batch analysis of the notes taken from the appellants was one which was created by Mr. Fletcher Burton, an employee of MSA Ltd, obtaining 97 bundles taken at random from used notes returned to the Bank of England. The other data base consisted at the time that the comparison was made, of 3,000 notes which had been obtained by MSA Ltd from High Street banks, mainly their own bank in Bristol. The point being made by Mr. Bottomley was that neither data base was, in his opinion, sufficient either in number, or as being relevant and representative as a sample of used bank notes, to be capable of providing a data base from which any secure conclusions could be reached. There was insufficient evidence to establish that they represented notes in "general circulation"; and, in particular, the absence of any data to show what level of contamination could be expected on notes handled by those involved in drug dealing. There was no material which could enable the jury to determine the significance of the findings made by Dr Sleeman.
He is a consultant forensic scientist and has been a member of the Forensic Science Service for many years. He is primarily a statistician, concerned with the presentation of forensic material to a court, and in particular the appropriate way in which to relate such material to the issues in a case. He provided two statements, of the 19th June 2003 and the 15th June 2004. In the first statement, he considered that the criticisms made by Mr. Bottomley of the databases used appeared to him to be persuasive, although he accepted that it was not his field. His main concern, however, was in relation to the statement in the summing-up to which we have already referred, that Dr Sleeman’s view was that the comparison made between the notes and the data base "points very strongly .... to the person holding those notes being very close to the source of contamination, and the sources of examination are drug users and drug dealers.".
In his opinion, that assertion could not be justified on the evidence, in the absence of any material to show the level of contamination which was the result of the handling of notes by drug users and drug dealers. In his second statement, he adhered to that view, making clear that it was only a criticism of Dr Sleeman if and in so far as the summing-up accurately reflected what Dr Sleeman had said.
Professor Laycock is Emeritus Professor of Statistics at UMIST Manchester. He has provided three reports, dated the 18th May 2004, the 11th June 2004, and the 2nd July 2004. He was highly critical of the use made of the two data bases. In his view they were wholly inadequate for the purposes of determining whether or not any given level of contamination was higher than normal in the general circulation. He pointed out that they constitute entirely random samples which have therefore no more statistical significance than that. In order to seek to establish what might be described as a normal level of contamination it would in his view be necessary to construct an appropriate sampling method so as to remove, or at least minimise the distortions which random sampling may produce. He accordingly concluded that no meaningful comparison could be made between the level of contamination on the notes and that in the two data bases.
Dr Sleeman has provided two reports, the first dated the 7th November 2003 and the second dated the 16th July 2004. In the first he was concerned to defend in the first instance the methodology of MSA Ltd and in particular the use of the DBC sampling technique as a reliable means of obtaining samples for the purposes of analysis. He accepted, as he had done at the trial, that innocent contamination was a relevant consideration and that the risk of innocent contamination was a matter which had to be taken into consideration when evaluating his findings and conclusions. He accepted, in particular, that he could not rule out the possibility that the officers who searched the car at Hull could have been responsible for the contamination found on the money and the car, but considered this extremely unlikely bearing in mind the high levels of cocaine in the car which would require the customs officers to have been contaminated to a high degree themselves to have produced those results; he said the same in relation to the risk of contamination of the bank notes. He further accepted, again as he had at the trial, that there was the possibility of contamination of the safe and the money in it, but that it was more likely that the protective suit was contaminated by the contents of the safe rather than vice versa. He further accepted that it was not safe in the light of the findings of contamination on the controls, and the unsatisfactory storage of the suitcases, to rely on the finding of contamination on the suitcases.
As far as the use of the data base was concerned, he considered that there was sufficient in each data base to entitle him to make a comparison between the two. He accepted that it was impossible to come to any statistically valid conclusion. In his view, he was, however, entitled to say from the material that he had that the higher the levels of the contamination, the more likely one is to be close to the source. He does not believe that the words used by the judge in the summing-up accurately reflected what he said; and there is certainly nothing in the notes of evidence which we have to that effect. In his view, the level of contamination was such as to justify his assertion, which was the limit of the importance which he placed upon that piece of evidence.
Professor Monoghan is the Professor of Chemistry at the University of Edinburgh. He provided two reports the first dated the 23rd January 2004 and the second the 18th June 2004. The first was essentially concerned with the methodology of the techniques used by MSA Ltd. In the second he stated that the validity of a data base depended on the purpose to which it was put. He considered that the data bases were sufficient for the purpose for which Dr Sleeman used them. He supported the robustness of the technique, whilst accepting that a court would have to look critically at the circumstances surrounding the taking of the samples in order to evaluate the risk of innocent contamination. In cross-examination, he accepted that the value of the data bases was limited but pointed out that there were no other data bases available at the time. He did not accept they had no value; and believed that they supported what Dr Sleeman had said.
Dr Brereton is a chemist with a specific interest in the statistical evaluation of chemical analyses. He provided the court with two reports, the first dated April 2004, and the second dated the 14th July 2004. In both reports he concluded that the databases, whilst limited, provided valid comparators, within their limits. He accepted that the statement attributed to Dr Sleeman by the judge in his summing-up overstated the case. But in his second report, he made the point that the extent to which contamination on the notes found in the appellants’ possession was such that there was, in his view, overwhelming evidence that the notes were close to the source of contamination. The question that had to be asked was whether or not the database was sufficient for the purpose of whatever comparison was being made. The comparison that was being made in this case was a very crude comparison for which the databases were sufficient.
It will be apparent from this recitation of the evidence at trial, the material before the commission, and the evidence before us, that there are three separate areas that need to be addressed. The first is the criticism of the methodology of the technique used by MSA Ltd. Mr. Blaxland, QC expressly abandoned any argument based upon this criticism. He was right to do so. In R v Compton  EWCA Crim 2835, this court had to consider criticisms made by Mr. Bottomley of the evidence of MSA Ltd, again given by Dr Sleeman. In that case, as here, his criticisms fell into three parts, first contamination, second methodology, and third the database. In paragraph 16 of the judgment of this court given by Buxton LJ, the court said:
.... When reading Mr. Bottomley’s report, and hearing his evidence in chief, we had the greatest difficulty in discerning how in fact he criticised MSA’s methodology; and in cross-examination it became clear that he did not do so. In response to Mr. Shay Mr. Bottomley confirmed that he had no criticism of the techniques used by MSA; no criticism of the scientific competence of MSA’s scientists; and no reason to doubt the accuracy of the readings obtained by MSA ....
As this judgment was given as long ago as the 11th December 2002, it is perhaps unfortunate that there was no recognition of the conclusions of this court in any of the material provided to this court by Mr. Bottomley. And it is significant that the criticism forms a major part of the reference by the Commission of the cases of these appellants to this court.
As far as contamination is concerned, we note that, despite the views of the Commission, none of the evidence before us suggests that there is any new material or criticism available to the appellants beyond that which was available at the trial and which was made by Mr. Young and acknowledged or dealt with by Dr Sleeman in his evidence. It is said on the appellant’s behalf that Dr Sleeman has now made three important concessions:
first, that there was the possibility of contamination of the car and the notes at Hull;
second that the risk of innocent contamination in relation to the findings in the safe and its contents was such that these findings should be discounted; and
third that the findings in relation to the suitcases were such that they should not have been used as part of the prosecution case at trial.
As to the first two, we consider that the submission overstates the concessions made by Dr Sleeman. Although he acknowledged the possibility of contamination by the customs officers at Hull, he considered that that possibility was highly unlikely. Equally, as far as the findings in relation to the safe and its contents were concerned, his evidence made it clear that they remained of evidential value subject to their evaluation, which was a matter for the jury, which had before it the criticisms which were acknowledged at the trial by Dr Sleeman and properly recorded in the summing-up by the judge.
The suitcases remain something of an enigma. Although Dr Sleeman told us that they formed no part of the prosecution case, it is apparent from the notes of his evidence that he placed some reliance on them. However, it is noteworthy that the judge did not refer to any of the suitcases apart from the two which he expressly reminded the jury should be ignored. Despite the further evidence from Mr. Bottomley as to the possibility that there may have been some cross-contamination between the bundles of notes found in the appellants possession, a point clearly available to Dr Young at the trial, we do not consider that any of this material would have had any effect on the jury’s verdicts.
This leaves, in relation to the evidence that we have heard, the issue relating to the data bases. We accept entirely the evidence of Professor Laycock that these could not properly provide any statistical basis for a conclusion as to the provenance of the suspect notes. But as he himself accepted in cross-examination, the question of the validity of a data base depends upon the purpose which is to be served. In the present case, the comparison made between the notes in the appellants’ possession and the data bases was merely part of the prosecution case showing a connection between the appellants and the cocaine. That was in the context of the other evidence which pointed, in the absence of any innocent explanation, to the fact that the appellants were involved in illicit activity which resulted in substantial financial gain. We do not consider that a jury, even confronted with the evidence of Professor Laycock, could have come to any other conclusion but that the levels of contamination here were significant. In Compton the court said this as to the argument in relation to the data base which was developed in that appeal:
The difficulty that we found with these arguments, was that if they were seriously to be pursued, they needed to be supported by the evidence of a statistician, which Mr. Bottomley plainly was not. Dr Sleeman explained that Lloyds was used because it was MSA’s own bank, and notes could therefore be obtained in the ordinary course of business; and that it could be assumed the ordinary process of circulation of notes through the banking system produced notes from a variety of sources. We found these observations convincing. Since the evidence on the part of the appellants amounts to no more than an appeal to common sense, we apply our own common sense to conclude that the range and weight of MSA’s database is sufficient for comparisons safely to be based on it.
There is, however, a further reason why we do not accept this part of the appellant’s argument. In this case, the difference between the levels of contamination found on the appellant’s money and the levels found on the money in ordinary circulation is so striking that even if some attack could be made on the margins of MSA’s database the discrepancy would still cry out for an explanation. For that reason, the explanations were properly required of the appellants at the trial explanations that the jury did not accept.
It is true that we have now had the benefit of evidence from statisticians. But that evidence does not, in our view, detract from the common sense views expressed in those paragraphs, and in particular in paragraph 28. They echo the evidence given to us by Professor Monaghan and Dr Brereton. We return to the point we have made about the context in which this evidence was adduced. The evidence as to contamination was not limited to the notes in the car. A critical feature of the case for the jury to evaluate was the evidence in relation to the contents of the vacuum cleaner and the contamination in the car. As the judge said, much in the case depended on the history of that vacuum cleaner and the jury’s assessment of the evidence given by the appellants in relation to it.
THE REAL ISSUE
It seems to us that the real issue which we have to determine is that which is raised, although perhaps not squarely, by Dr Evett. There were two aspects of the summing-up which would appear to have misstated the prosecution case. Dr Sleeman has disavowed the evidence attributed to him by the judge in his summing-up; and in the immediately following passage, to which we have already referred, the judge raised the question of the lottery in a way which may have suggested that it was part of the prosecution case that the coincidences required for the appellants’ case to be credible were such as to be equated to winning the lottery. We have no reason to doubt Dr Sleeman’s evidence to us that he did not make the statement attributed to him. Equally, there is no doubt that the judge was wrong to have sought in any way to suggest that the appellants’ case was somehow analogous to requiring the jury to assess the likelihood of their account being correct in that way. But the fact of the matter is that the prosecution case was, in our view, overwhelming. As we have said, all the evidence pointed to the appellants having been engaged in illicit activity. The finding of cocaine contamination, in particular in the dust in the vacuum cleaner and in the car pointed clearly to that illicit activity being drug, in particular cocaine, related. Accordingly we conclude that the evidence that we have heard, subject to the matters to which we now turn, was a secure and safe basis for the verdicts of the jury.
THE JUDGE'S DIRECTIONS AS TO SECTIONS 34 AND 36
The summing-up in the present case was given by the judge before this court had given detailed guidance as to the way in which the jury should be directed when considering these provisions. It is perhaps helpful to give the full passage in the summing-up in which the judge dealt with this matter. It starts at page 10:
Each of the defendants as part of their defence have relied upon explanations of information or assertions of fact. Can I list those: as to the source of the money seized at Hull Mr. Benn has given explanation which are also relied upon by |Mrs. Benn as to where that money came from; as to how cocaine could have contaminated the interior of the vacuum cleaner which was seized on the 19th March 1996, the vacuum cleaner which may have been at a hotel in Blackpool and become contaminated there; as to how the BMW car which was tested on the 19th March may have been contaminated by transporting the same vacuum cleaner, itself already perhaps contaminated with cocaine from Blackpool; and as to how the money was earned which was deposited in bank accounts or used to discharge Barclaycard Account liabilities, discharged part of the mortgage, the judgment debts and the costs and to pay for expensive building work, motor cars and support an expensive life style and allow for the accumulation of large sums in cash, and that, of course, is the sale of pirate video cards; as to the purpose and frequency of foreign travel and perhaps being accompanied by children on occasions.
Now the two defendants both admit that they did not mention any of those facts when they were questioned under caution by the Customs Officers on the 20th March and I think 16th April – I cant remember, 17th April sorry, I was a day wrong members of the jury. Now the prosecution case is that in the circumstances when each of them were questioned he or she could reasonably have been expected to mention those facts. Each defendant has said that they could have given those explanation. Indeed one, Ronald Benn went so far as to agree with the prosecution’s suggestion that he was itching to give those explanations. But each say that they were precluded from doing so because of advice from their solicitor Mr. Gareth Hughes, or in the case of Mrs. Benn, Gareth Hughes through his agent Mr. Laverton who was actually with her at those interviews that she gave.
But the law is, members of the jury, that a suspect person, a defendant I suppose ultimately, cannot be made to answer questions, that is his or her right . Frequently that is called the right to silence. But because in the past some defendants have been thought to have been sprung defences on the prosecution and the courts, that is to say kept silent until the day of the trial and then revealed the defence which was too late to check up on and to verify, Parliament has enacted now that the person being questioned must be given a new form of caution. That caution amounts to this: that if he or she fails to reveal something when questioned, something which he or she later relies upon in court, it may harm their defence. The is the first thing.
It is the law, members of the jury, that you as the jury trying the case may draw such inferences as appear proper from his or her failure to do so at that time.
Now, members of the jury, failure to mention a fact on its own cannot prove guilt, there must be some other evidence which also points against the defendant before any inference can be drawn from silence. But depending on the circumstances, members of the jury, you may hold it against a person when deciding whether he or she is guilty, that is take into account some, additional support for the prosecution case, but you are not bound to do so and it is for you to decide whether it is fair to do so.
Now, members of the jury, each of the defendants have told you they relied on Mr. Hughes advice in making their no comment answers. At the beginning of each interview Mr. Hughes in his case – against Mr. Benn – Mr. Laverton his agent in the case of Mrs. Benn, read out what was obviously a pre-prepared statement in identical terms as to why they were giving that advice.
Now members of the jury, advice from a solicitor not to reveal facts when questioned is on its own not a sufficient reason for failing to do so. Members of the jury, if that were the case any competent solicitor could render the Act of Parliament wholly nugatory. Parliament has said that if a person fails to reveal something when questioned, if it is reasonable to expect him to do so and he fails to do so, then inferences can be drawn against him by the jury. And if a solicitor simply said "Don’t answer that question", the whole Act of Parliament has completely gone out of the window and solicitors do not have that competence.
The defendant Ronald Benn has told you that he explained all the facts to Gareth Hughes, his solicitor, before that advice was given. Sylvia Benn has merely said that she had to act on her solicitor’s advice. You have not heard from Gareth Hughes or Mr. Laverton as to the basis for the reasons for the advice they gave. If the assertions made by the solicitor before the commencement of the interviews are to be taken at face value, what they were saying was two things: first that there were many documents which had been seized and that made matters too complicated to answer the questions adequately; and two, that the Benn’s had lost confidence in the integrity of the proceedings regarding the seizure of the £62,000 or thereabouts and the application for its forfeiture.
Now neither of the Benns have made any assertion that second proposition was true, they’ve not supported it by any evidence. As to the first proposition, you are aware of the questions that were asked and answers which have now been given in evidence before you. So the question you have to address is this; whether in all the circumstance which existed at the time that the questions were asked could either person whose case you are considering Mr. or Mrs. Benn, reasonably be expected to mention those facts.
Now the defence invite you not to hold it against them that they did not mention those facts or on that basis. If you think it amounts to a reason well then you shouldn’t hold it against them that they failed to do so. If on the other hand it does not provide an adequate explanation or you are sure the real reason for the failure to mention those facts was that he or she at that time no innocent explanation to offer, then you may hold it against him or her.
Now all of that I have just said applies equally in relation to the defendants failure to give any explanation at the time about the presence of cocaine contamination both in the vacuum cleaner and in the safe and the contents of the safe and in the car because the Customs officers specifically asked for an explanation of the presence of cocaine in those places and in those vehicles. The defendants failed to answer.
Now, members of the jury, failure when an officer has reasonable suspicion to ask questions, he has got cause to ask those questions, he wants an explanation – lets go outside this case just to explain what I mean. If a police officer investigating, shall we say a murder or a stabbing finds a man with a knife in his hand and blood on his clothing and sees him in circumstances which leads the officer to conclude that person might have something to do with it, he can ask him, "now would you explain that knife in your hand, that blood on your clothing". If he fails to do so and there is other evidence against that person as well, it may not necessarily amount to very much but to some evidence against him outside that, if he fails to give an explanation the jury may think it right to hold that against the defendant if he fails to do so.
And as regards the cocaine – the presence of the cocaine in the vacuum cleaner, in the car and in the safe, neither defendant, when specifically asked as to specifically warned gave any answers about that members of the jury what I said previously about inferences that you, the jury, may draw, if you think it is proper to do so if you are satisfied that there is no proper explanation may draw an inference as an additional material in support of the prosecution case.
It is submitted there are two main vices in that direction.
The first is that as this court made plain in Condron v Condron  1 Cr App R. 185, the judge must make it clear to the jury that before any adverse inference may be drawn, there has to be a case for that defendant to answer. Silence or a refusal to answer questions is not enough. That can never be a proper foundation for a conviction.
The second is that the judge failed to direct the jury that they could only draw an adverse inference if satisfied that silence meant that they had no explanation or no explanation that would survive questioning.
There is no doubt that the judge in the present case failed to direct the jury as to this requirement in the way now recommended by the Judicial Studies Board. The nearest that he came to doing so in relation to the first requirement is in the passage where he said failure to mention a fact on its own could not prove guilt and there must be some other evidence which also points against a defendant before any inference can be drawn from silence. Further, he referred to the fact that the other evidence "may not necessarily amount to very much but to some evidence against him", which was also a direction which was insufficiently clear in this respect. The fact of the matter is however that in this case there was an abundance of evidence which established that the prosecution had surmounted the hurdle of establishing a case to answer. The judge in the passage where he set out the matters which cried out for an explanation clearly makes that point. The jury was bound to have come to that conclusion had they been fully and properly directed.
The real question, it seems to us, is whether the judge dealt properly with the second of the two main requirements, namely that he should have given the jury proper assistance as to the approach it should take to the fact that the appellants had received legal advice not to answer any questions. There is no doubt that he was right to direct the jury that they could take into account the reasons given by the solicitors for their advice. The jury were entitled to take those reasons into account when determining whether or not their reason for refusing to answer the questions was in truth because of that advice. But in Condron v UK (2001) 31 ECHRR 1 the European Court of Human Rights made it plain that an adverse inference could only properly be drawn if their refusal to answer questions was because they had no answer or none that would stand up to cross examination. Although this trial took place before the enactment of the Human Rights Act 1998, we accept that that is a principle which should nonetheless be adopted in determining whether or not the direction adequately protected the appellants’ rights to silence.
In R v Betts & Hall  2 Cr App R 257, this court said that the effect of this decision on a case where an appellant had received legal advice not to answer questions, was that it was the genuineness of the decision which is relevant and not its quality. In other words the jury had to determine whether or not the real reason for the appellant’s silence was because of the legal advice that he or she had received or was in truth that they had no or no adequate explanation to give to the case against them. In R v Hoare & Pierce  EWCA Crim 784, Auld LJ said in giving the judgment of this court:
The question in the end, it is for the jury, is whether regardless of advice, genuinely given and genuinely accepted, an accused has remained silent not because of that advice but because he had no or no satisfactory explanation to give. For this purpose, but only for this purpose, section 34 in its provision for the drawing of an adverse inference qualifies a defendants right to silence.
It is submitted on behalf of the appellants that the judge did not adequately direct the jury in this fundamental respect. It is said that in the passage to which we have referred, the judge sought to undermine this principle in particular by his remarks about the effect that solicitors advice could have on Parliament’s intentions. It is said that the judge in effect directed the jury to consider the reasonableness of the appellants’ decision not to answer the questions, and not its genuineness. The critical passage is the passage in which he said:
On the other hand if it does not provide an adequate explanation or you are sure that the real reason for the failure to mention these facts was that he or she at that time had no innocent explanation to offer, then you may hold it against him or her.
The disjunctive "or" is said to deprive that passage of the necessary quality of ensuring that the jury understood that it was only the latter circumstance which could entitle it to draw the adverse inference.
There is no doubt that this passage is capable of criticism. But in reality, it seems to us, the jury was there being directed that the important question was what the real reason for their failure to answer the questions was, and that that was the touchstone for determining whether they had an adequate explanation for failing to answer the questions. Accordingly, although the direction is not in the form which is now recommended so as to avoid any doubt as to the matter, this passage adequately reflects the requirements that the courts have constructed to protect the right to silence.
A subsidiary matter was raised by Mr. Jennings, QC on behalf of Mrs. Benn, namely that the judge was wrong to identify the questions as to how the cocaine could have contaminated the vacuum cleaner used at the Blackpool hotel, and how the BMW could have been contaminated by transporting the vacuum cleaner from the hotel to the home as being facts on which the appellant’s relied at trial and failed to mention in their interviews. It is said that these amounted to speculation. We fail to understand this submission. The appellants were made aware of the cocaine found in the dust bag of the vacuum cleaner. They knew if they were telling the truth, that the vacuum cleaner could have been the one used at the Blackpool hotel and therefore could have been transported in the BMW. Those were explanations which they could have given in answer to the questions, alternatively, if they were at the time in doubt about the matter they could have expressed their doubts in those terms. If they were in such doubt they could have explained that to the jury as a reason for not mentioning those facts. It would have then been for the jury to evaluate their answers.
As a late addition to the case, Mr. Blaxland, QC as we have already said, pointed out that there was no direction to the jury as how to approach any lies which they may have found the appellants to have told. It is true that no such direction appears in the summing up. The problem is that that is a matter which could and, if it was a proper complaint, should have been made either at the trial, or at the time of the first appeal, or during the course of the reference to this court. We think that it is too late to raise that issue now. There may well have been good reasons for that direction to have been omitted. In those circumstances, it does not appear to us that it can form any part of the grounds of appeal which we should consider.
For all these reasons, these appeals are dismissed.
R v Compton  EWCA Crim 2835
Condron v Condron  1 Cr App R. 185
Condron v UK (2001) 31 ECHRR 1
R v Betts & Hall  2 Cr App R 257
R v Hoare & Pierce  EWCA Crim 784
Criminal Justice and Public Order Act 1994: s.34, s.36
Criminal Appeal Act 1968: s.23
Mr. CH Blaxland, QC and Mr. J Gregory (instructed by Stephensons) for the Appellant Kevin Benn
Mr. AF Jennings QC and Maya Sikand (instructed by Stephensons) for the Appellant Sylvia Benn
Mr. David Barnard & Mark Stanger (instructed by HM Customs & Excise, Prosecution Group) for the Respondent
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