Submitted by Professor Adrian Keane (CA 25)
Is there a weakness in the current law on "similar fact evidence"?
1. There is a significant weakness in the current law on so-called similar fact evidence. It relates to the risk of collusion between witnesses, which can result in miscarriages of justice, and is the result of the decision of the House of Lords in R v H (1995) 2 AC 596. The danger manifests itself in a variety of cases, including those involving abuse in children's homes, in which the evidence relates to a number of separate but similar incidents. These are often cases in which the indictment contains a number of counts and the prosecution evidence on each count is treated as similar fact evidence relevant to the question of guilt on the other counts.
2. The law relating to similar fact evidence is complex and its application fraught with difficulties. Under the modern law, however, the main principles can be stated with comparative ease. Evidence of the accused's disposition towards wrongdoing or of specific acts of misconduct (whether or not they resulted in previous convictions) is generally inadmissible to prove guilt. Although such evidence may be regarded as relevant, the law excludes it because of the danger that it might unduly influence the jury against the accused. The jury may attach to it a weight out of all proportion to its true probative value. Proof that a person has a disposition to act in a particular way may lead to the unwarranted inference that on a particular occasion he acted in that way. Normally, therefore, the evidence is excluded or, in cases with a multiple-count indictment, the jury are directed to consider the evidence on each count separately and not to use evidence on one count as evidence of guilt on another. It is otherwise, however, if the judge classifies the evidence as similar fact evidence. The leading authority is DPP v P (1991) 2 AC 447, which lowered the standard for admissibility. Lord Mackay LC held that "the judge must . . . decide whether there is material upon which the jury would be entitled to conclude that evidence of one victim, about what occurred to that victim, is so related to the evidence given by another victim, about what happened to that other victim, that the evidence of the first victim provides strong enough support for the evidence of the second victim to make it just to admit it, notwithstanding the prejudicial effect of admitting the evidence". It was also held that although the requisite probative value may be derived from striking similarities between the evidence of the victims, striking similarities or "unusual characteristics" are not essential. Previous authorities had held that evidence could not be treated as similar fact evidence without some feature of similarity going beyond, in cases of alleged sexual abuse of children, "the pederast's . . . stock-in-trade". They were overruled.
3. In some cases there is a real risk of collusion between victims or contamination of their evidence. This risk arises where there is evidence to suggest that the complainants have deliberately concocted false evidence by conspiracy or collaboration and also, which is probably much more common, where their evidence has been innocently contaminated, ie influenced by knowledge of the account of another victim, whether acquired from direct discussion with another victim, indirectly through a third party, eg a social services department seeking potential complainants, or from media publicity. The problem is compounded, of course, if there is a prospect of compensation or some other motive for giving false evidence. Until R v H the preponderance of authority favoured the judicial exclusion of such tainted evidence. There are cogent reasons to support such exclusion. If, there being no question of collusion or contamination, a number of witnesses give evidence of separate but similar incidents, their evidence has probative force because of the unlikelihood of coincidence, and the greater the number of incidents and the more striking or unusual the similarities, then the greater the probative force of their evidence. To the extent, therefore, that the similarities are the result of collusion or contamination, the probative force disappears. Prior to R v H there was reasonably clear authority that if there is a real risk of collusion, the evidence should be excluded rather than left to the jury with a suitable warning. In R v H these cases were overruled.
4. R v H involved sexual offences against a daughter and a step-daughter between whom, the parties agreed, there existed a risk of collusion. Lord Mackay LC held as follows.
(i) Where there is an application to exclude evidence on the ground that it does not qualify as similar fact evidence and the submission raises a question of collusion, the judge should decide the question of admissibility on the basis that the similar facts are true and apply the test in R v P. Generally collusion is not relevant at this stage.
(ii) If a submission is made raising a question of collusion in such a way as to cause the judge difficulty in applying the test in R v P, the judge may be compelled to hold a trial within a trial to decide admissibility. This would arise only in a very exceptional case (so very exceptional that no illustration could be given).
(iii) If the evidence is admitted and evidence is also adduced in the course of the trial which indicates that no reasonable jury could accept the evidence as free from collusion, the judge should direct the jury that it cannot be relied upon as corroboration or for any other purpose adverse to the defence.
(iv) Where this is not so but the question of collusion has been raised, the judge must direct the jury that they may rely upon the evidence as corroboration if satisfied that it is free from collusion, but that if not so satisfied they cannot rely upon it as corroboration or for any other purpose adverse to the defence.
5. The reasoning of the House of Lords was that it would be wrong for the judge to rule on the question of collusion because he would inevitably be drawn into considering whether the evidence is untrue and hence whether there is a possibility that the accused is innocent, the very question for the jury. Underlying the decision of the House there also appears to be an erroneous assumption that if the question of admissibility is left to the judge, cases involving allegations by victims who are well known to each other, such as siblings or inmates of children's homes, will become incapable of prosecution. The dangers of admitting contaminated evidence have been seriously underplayed by the House. There can be no guarantee that directions of the kind set out in (iii) and (iv) above will have the effect of removing the obvious prejudice likely to be caused by admission of the evidence. In other words, there is a serious risk that notwithstanding such directions, the jury will follow a forbidden line of reasoning that since the accused appears to have the disposition towards the type of misconduct in question, he is guilty of the misconduct alleged. If a conviction results, it is, in effect unappealable. The record will show that the judge properly applied the test under R v P and then directed the jury in accordance with R v H but not, of course, what happened in the jury room.