Delayed Complaint, Lost Evidence and Fair Trial: Epistemic and Non-epistemic Concerns


Delayed Complaint, Lost Evidence and Fair Trial: Epistemic and Non-epistemic Concerns



JUDICIAL CONCERN ABOUT the impact of delayed complaints on the fairness of trials and the safety of convictions is not a recent phenomenon. As long ago as 1844 Baron Alderson declared:

It is monstrous to put a man on his trial after such a lapse of time. How can he account for his conduct so far back? If you accuse a man of a crime the next day, he may be enabled to bring forward his servants and family to say where he was and what he was about at the time; but if the charge be not preferred for a year or more, how can he clear himself? No man’s life would be safe if such a prosecution were permitted. It would be very unjust to put him on his trial.1

In recent decades courts have expressed similar concerns as they have faced increasing numbers of delayed child sexual assault prosecutions. English juries should be directed to:

[C]onsider the effect which the passage of time has had upon the defendant’s ability to respond. He did not know, until recently, that he would have to meet the case now brought against him…. If, having considered the defendant’s position, you accept that he has, as a result of the delay, been placed at a material disadvantage, you should consider carefully to what extent that concern might influence your conclusion.2

In Australia, at common law, the jury should be instructed:

[A]s the evidence of the complainant could not be adequately tested after the passage of [however many] years, it would be dangerous to convict on that evidence alone unless the jury, scrutinising the evidence with great care, considering the circumstances relevant to its evaluation and paying heed to the warning, were satisfied of its truth and accuracy.3

The Australian direction has been described as ‘a not too subtle encouragement by the trial judge to acquit’4 and has been toned down in recent legislation.5 In these and other jurisdictions the trial judge may take the view that the effects of delay are so severe that the trial should be stayed altogether.6

This chapter examines the justification for these pro-defendant interventions. On first impression they appear to have an epistemic basis. Evidence has been lost through delay, and it is difficult to test properly the little evidence that remains. But as I explore below, it is not clear why this should elicit a pro-defendant response. Missing evidence appears to be just as great a problem for the prosecution, possibly greater in view of the presumption of innocence. Pro-defendant interventions seem to distort the proper inferential processes. Epistemically, the best way to resolve these cases is to simply assess the strength of the available evidence.

If pro-defendant interventions lack an epistemic basis, they may instead have a non-epistemic foundation. The defendant’s position is certainly troubling: accused many years after the alleged assault, unable to gather evidence owing to the delay, his defence reduced to one of a bare denial. Perhaps the underlying concern is the defendant’s objectification and lack of opportunity to participate in the trial. This non-epistemic rationale does not suffer the logical flaws of the epistemic arguments, but it does not appear strong enough to justify judicial interventions. The primary justification for the defendant’s right to present a defence is not the non-epistemic value of autonomy, but rather to assist the court’s epistemic, fact-finding endeavour. Where the defendant’s participatory rights clash with the epistemic goal, the latter generally prevails.


Specifically epistemic objections to criminal prosecutions arising from delayed complaints can be divided into the following three categories: (a) weakness of the prosecution case; (b) defendants’ forensic disadvantage; and (c) lack of evidential weight. This section examines each strand of argument in turn.

(a) Weakness of the Prosecution Case

In many delayed complaint cases, the prosecution evidence is little more than the complainant’s testimony. Perhaps the most obvious explanation for a pro-defendant intervention is that, given the prosecution’s heavy burden of proof, a conviction would be untenable.

At an earlier stage in the law’s development this view would have had greater force. The absence of a prompt complaint was considered to weaken the complainant’s credibility. The law assumed that, had the offence actually taken place as alleged, the complainant would have raised an immediate hue and cry.7 There may also have been an element of best evidence reasoning at play. To block delayed prosecutions may motivate prompter complaint, avoiding the loss of evidence.8 Today, however, it is recognised that there are many reasons for a child sexual assault victim to delay complaint, such as ‘embarrassment, fear, guilt, or a lack of understanding and knowledge’.9 And, of course, to discount the complainant’s credibility would hardly motivate a victim to come forward more promptly. The opposite is more likely. In the modern law, reflecting this increased understanding,

the timing of the complaint is simply one circumstance to consider in the factual mosaic of a particular case. A delay in disclosure, standing alone, will never give rise to an adverse inference against the credibility of the complainant.10

Even without any adverse inference working against the complainant, delay will often weaken the prosecution case. It is not only that the complainant’s evidence is uncorroborated. As a result of the delay the complainant’s account will often lack persuasive detail. This in turn makes it difficult for the defendant to test the complainant’s evidence through cross-examination directed at revealing inconsistencies and contradictions.11 Uncorroborated, undetailed, untested complainant testimony will generally struggle to satisfy a jury beyond reasonable doubt of the defendant’s guilt. Hardiman J of the Supreme Court of Ireland stated:

It would be quite wrong to convict a person of a serious offence, likely to lead to prolonged imprisonment, social, familial and often financial destruction, and lifelong stigmatisation as a sex offender, purely on the basis of impression, as opposed to reason.12

According to Hardiman J, prosecutions that are ‘pure contest[s] of credibility’ with ‘no island of facts’ should not be allowed to proceed.13

Hardiman J’s ‘island of fact’ principle was rightly rejected by a majority of the Irish Supreme Court.14 It would, in effect, reinstate the much criticised corroboration requirement. Sexual assault complainants—mostly women and children—would be treated as inherently suspect witnesses, a classification which has previously been said to reflect ‘the limitations on the experience of judges, who were almost invariably male’15 and to reveal ‘the law itself rather than the witness or her evidence [as] distinctly suspect’.16 Such a requirement would render many sexual assault prosecutions ‘impossible’.17 Not only in delay cases, but also in acquaintance rape prosecutions, it is not uncommon for there to be no eyewitnesses and no incriminating scientific or medical evidence.18

An inflexible demand for corroboration of the complainant’s allegations would be over-inclusive. While, as a generalisation, delayed prosecutions may lack sufficient strength to secure conviction, there will inevitably be exceptions. In Longman,19 for example, Deane J observed that

the evidence of the complainant reads convincingly. It is not surprising that the jury accepted her as an honest witness. The same could not be said of the evidence of the applicant… It is not surprising that the jury plainly rejected the applicant as a witness.20

Complainants will often gain an advantage in the credibility stakes on the basis that there is no apparent reason for them to lie, whereas defendants have a clear interest in proclaiming their innocence whether true or not. Of course, care must be taken in this kind of reasoning not to infringe the presumption of innocence.21 Defendants bear no burden of proof with respect to the truthfulness or motivations of complainants. The question is not merely who, between the defendant and complainant, is more believable. The prosecution bears the burden of eliminating all reasonable doubt about the defendant’s guilt. And the defendant should not be treated as an inherently suspect witness requiring heightened scrutiny.22 But this does not alter the fact that the defendant generally has the greatest stake in the outcome of a criminal trial. That is why the presumption of innocence demands such a high level of certainty for conviction.23 Another consequence is that the defendant’s interest in the outcome tends to swamp the probative value of other evidence going to his credibility.24 Having regard to the parties’ relative motivations for lying, it is not impossible that the complainant’s credibility will sufficiently outweigh the defendant’s credibility for a conviction to be secured.

A further question that Hardiman J’s proposal raises is why judicial intervention should be necessary. He assumes not only that the prosecution’s case has been fatally weakened as a result of the delay and consequent loss of evidence, but also that a jury would fail to appreciate the salience of these evidential infirmities. Hardiman J suggests that ‘[a] purely impressionistic decision is as likely to be wrong as right, and one cannot hope to justify it objectively’.25 There is certainly a wealth of empirical data supporting the view that credibility assessments resting on demeanour alone are of dubious reliability,26 but it does not follow that the defendant’s position ‘is indeed perilous’27 or that ‘[t]he possibilities of success of either side [are] haphazard’.28 The presumption of innocence stacks the odds against the prosecution and, despite Hardiman J’s claims29 empirical data does not show that juries’ credibility assessments are biased in favour of complainants. If anything, there appears to be a bias against complainants. Credibility assessments are mediated by cultural stereotypes and misconceptions that work against complainants.30 The complainant’s passivity during the alleged assault, subsequent delay in complaint, or maintenance of a relatively normal relationship with the alleged perpetrator following the alleged assault may reduce the complainant’s credibility with a jury, notwithstanding that these are relatively common features of such acquaintance rape. The subjectivities and vagaries of credibility assessments in sexual assault cases tend to add to the difficulties of enforcement,31 not to the risk of wrongful conviction.

(b) Defendants’ Forensic Disadvantage

Delay will often weaken the prosecution’s case, but not necessarily fatally. Furthermore, there is no general tendency for juries to overvalue complainant testimony. If pro-defendant judicial intervention in delayed complaint trials is justified, it must appeal to some specific rationale other than the inherent and unappreciated weakness of prosecution evidence.

Many courts and commentators suggest that the defendant suffers forensic disadvantage from delay and the associated loss of evidence. The Judicial Studies Board direction quoted above,32 for example, refers to ‘the effect which the passage of time has had upon the defendant’s ability to respond’ to the charges, the possibility that the defendant has ‘been placed at a material disadvantage’, and the need for the jury to ‘consider carefully to what extent that concern might influence [its] conclusion’. The defendant, for example, may have been deprived of the opportunity to advance an alibi,33 or to obtain exculpatory scientific evidence.34

There is a tension between this view and the argument considered in the previous section.35 To suggest that delay weakens the prosecution case is to highlight missing prosecution evidence. The present forensic disadvantage argument draws attention to missing defence evidence. Given this rough symmetry, how can both considerations favour pro-defendant intervention? There is no sensible answer to this question. On examination, as I have explained elsewhere,36 the forensic disadvantage argument suffers from a fatal logical flaw.

Evidence has been lost because of the delay. Because the evidence is lost its content is unknown.37 Would the missing witnesses have confirmed the defendant’s alibi, or demonstrated the defendant’s opportunity? Would forensic science examinations of the alleged scene of abuse have revealed semen stains or clean sheets? The answers remain unknown. Logically, the loss of evidence can cause only possible prejudice to the defendant. However, from the court’s point of view, this possibility is balanced by the opposite possibility that the loss prejudiced the prosecution.

It might be argued that a corollary of the presumption of innocence is that the lost evidence must be assumed to be exculpatory.38 But this would give the presumption too much force.39 The presumption demands a high level of proof for conviction, but it clearly allows for the possibility of the defendant’s guilt. It is not contrary to the presumption to accommodate the possibility of the defendant’s guilt in measuring the strength of the prosecution evidence. To reject this possibility would defeat the purpose of the trial.

Occasionally judges recognise the balance in risks of forensic disadvantage. Hardiman J asserted that ‘long delay prejudices the defendant disproportionately, and may actually assist the prosecution’,40 but his fellow judges retorted that ‘delay is damaging to both parties’.41 In R v M42 the defendant objected that the delayed complaint had deprived him of the opportunity to have the complainant undergo a medical examination, proving that she was a virgin following the alleged sexual assault. The English Court of Appeal responded: ‘[t]he reality is that, had there been a medical examination … it might have provided the most damaging evidence against the defendant’.43 Justice Vanstone in the South Australian Court of Criminal Appeal pointed out that ‘since [the defendant’s] forensic difficulties were to be assumed… then as a matter of logic, similar difficulties could be assumed to have faced the complainants’.44 In a New South Wales decision, Chief Justice at Common Law Wood noted that ‘the impact of the delay is double edged, since it is just as likely to occasion practical difficulty for the prosecution’.45

But these observations are exceptions to the prevailing forensic illogic. Wood CJ at CL was bound by High Court authority to hold that ‘the absence of contemporaneity between the alleged offence and complaint, or trial has in fact (not “might have”) denied to the accused a proper opportunity to meet the charge or charges brought’.46 And the English Court of Appeal criticised a trial judge who had ‘even-handedly draw[n] attention [to the] potential impact [of delay] upon the Crown evidence’ for having ‘wrongly equated the problems confronting both Crown and Defence’.47 Illogical though it is, the assumption that only the defendant suffers forensic disadvantage is presented as a key justification for judicial intervention in delayed complaint trials.

(c) Lack of Evidential Weight

We have so far considered two epistemic concerns with delayed sexual assault prosecutions. A third interpretation of the epistemic concerns arising from delay proposes that the prosecution standard of proof requires not only that evidence have sufficient strength, but that it also have sufficient weight.

The distinction between strength and weight was noted by John Maynard Keynes. The strength of a body of evidence, Keynes said, ‘depends upon a balance between the favourable and the unfavourable evidence’.48 The weight of a body of evidence, however, ‘turns upon a balance … between the absolute amount of relevant knowledge and of relevant ignorance respectively’.49 In delayed complaint cases, evidence may appear sufficiently strong for conviction. As noted above, in Longman Deane J considered that the complainant was far more credible than the defendant.50 The balance of available evidence strongly favoured the prosecution. Deane J then added: ‘All that having been said however, the fact remains that the only evidence of the applicant’s guilt … was the oral evidence of the complainant’.51 Deane J was concerned that the evidence lacked sufficient weight. Because of the delay there were no corroborating witnesses and no forensic or medical evidence. The weight of the available evidence was too slight; too much evidence had been lost. The balance was tipped too far towards ignorance rather than knowledge.

The clearest illustrations of a divergence between weight and strength of evidence, far removed from delayed complaint cases, are the ‘naked statistical evidence’52 (NSE) hypotheticals, much discussed by evidence theorists. In the Blue Bus case, having been hit by an unidentified bus, the plaintiff sues the Blue Bus Co, as they own 80 per cent of the buses in town.53 In the Prisoners case, 999 out of 1000 prisoners are involved in the killing of another prisoner. The defendant is charged purely on the basis that he is one of the 1000.54 In each case the statistical evidence generates a probability figure that appears to satisfy the applicable standard of proof—0.80 and 0.999 respectively. The evidence appears to possess sufficient strength. However, most commentators consider that both the plaintiff and the prosecution would fail.55 Although probabilistically strong, the evidence lacks sufficient ‘weight’,56 ‘completeness’57 or ‘comprehensiveness’.58

The weight concept plausibly explains our resistance to making a positive finding in both NSE and delayed complaint cases. But its normative status is more ambiguous. Clearly a greater weight of evidence is preferable to a lesser weight. To question this would imply scepticism about the viability of the fact-finding venture.59 Fact-finding presupposes the value of evidence. Where uncertainty exists, fresh evidence will be welcomed in the expectation that it will produce a better decision.60 Losing evidence through delay reduces the ‘chances of the Courts being able to find out what really happened’;61 ‘the likelihood of error increases’.62 But what implications does this carry for low weight cases? In many contexts it will be sensible for a decision-maker to resist committing herself on the basis of a slight weight of evidence. Such reluctance may be a useful heuristic,63 prompting the search for further evidence and consequently generating a better-informed decision. Imposing an evidential weight requirement on a litigant with access to additional evidence may have the benefit of increasing the overall quantity of evidence available to the fact-finder and improving the accuracy of the verdict.64

But these evidential weight requirements will create positive incentives only where further evidence is available to be found and taken into account.65 This will rarely be the case in delayed complaint cases. A weight requirement will not motivate child sexual assault complainants to come forward earlier. The prosecution will not miraculously unearth lost evidence. A weight requirement, in short, would serve no useful purpose here. From an epistemic point of view, the fact-finder should proceed on the evidence that is available. If the complainant’s evidence is sufficiently strong, conviction is the most appropriate result. Lack of weight should pose no obstacle. The ‘wait for further evidence’ heuristic is counterproductive, potentially producing a ‘severe and systematic bias’,66 increasing mistaken acquittals, and undermining the prohibition against sexual assault.


Epistemically, delayed sexual assault prosecutions do not threaten the fairness of a trial. There is no heightened risk of wrongful conviction. Evidence that has been lost could have gone either way. The court should not be distracted by the possibility of missing evidence but should decide on the basis of the strength of the evidence that is available. To do otherwise will just add further to the enforcement difficulties in this area. From the point of view of factual accuracy, pro-defendant interventions are unjustified.

However, the loss of evidence in delayed complaint trials may raise non-epistemic concerns beyond any implications for the accuracy of the final verdict. According to Hardiman J, such cases lack ‘the fundamental nature of a trial’:67 ‘[A] forensic inquiry proceeds as far as possible upon evidence… [E]ach of the protagonists in such a trial seeks to offer reasons why the result it urges should be arrived at’.68 Where a complaint has been delayed, evidence and reasons may be in short supply. A trial consisting of a bare allegation and a bare denial is ‘scarcely a forensic contest at all’.69 Indeed, ‘the lapse of time may be so great as to deprive the party against whom an allegation is made of his “capacity … to be effectively heard”’.70 Hardiman J suggests that, in this respect, delayed complaint trials cannot possibly be fair trials.

The US Supreme Court has observed on numerous occasions that ‘an essential component of procedural fairness is an opportunity to be heard’.71 And in Canada, ‘[t]he right to make full answer and defence is… one of the principles of fundamental justice’.72 Others have not drawn the connection as explicitly as Hardiman J, but the defendant responding to a delayed complaint resembles other types of defendant who have been deprived of this right: the defendant lacking adequate notice of the prosecution’s case, and thereby denied ‘a reasonable opportunity to meet [the charges against him] by way of defense or explanation’;73 the defendant deprived of competent representation through counsel’s ‘(1) failing to investigate [a] potential defence; (2) failing to present crucial evidence; [or] (3) failing to impeach a prosecution witness’;74 the incompetent defendant ‘whose capacity for self-determination is compromised to such a degree and in such a way that she could not be anything more than an object of inquiry that passively undergoes processing and eventual labelling’.75

On this view, delayed complaint trials may not create a heightened risk of wrongful conviction, but they objectify the defendant and ‘convictions … may be obtained at too high a price’.76 However, this argument faces a significant obstacle. While it is possible to identify a non-epistemic basis for the right to present a defence, the right also has a strong epistemic basis. The defendant’s participation generally assists the court in arriving at the truth. Where the two rationales diverge, allowing less defendant participation may appear preferable to increasing the risk of factual error. To privilege participation over accuracy may reflect not respect for the defendant’s autonomy, but an attachment to a dubious sporting or ‘fight theory’ of the trial.

(a) Non-epistemic Value of Participation