Recalibrating Collateral and Sexual History Evidence in Scottish Sexual Offence Trials: Article 6 Requires a Nuanced s 275 Balancing Approach

Case: Daly v His Majesty’s Advocate & Anor (Scotland)

Citation: [2025] UKSC 38

Court: United Kingdom Supreme Court

Date: 12 November 2025

Panel: Lord Reed (giving the judgment), with whom Lord Hodge, Lord Hamblen, Lady Rose and Lady Simler agreed

Introduction

This landmark decision addresses “compatibility issues” under sections 288ZA and 288AA of the Criminal Procedure (Scotland) Act 1995 (the 1995 Act) in two Scottish sexual offence prosecutions. At its core lies a systemic question: is the approach of the High Court of Justiciary Appeal Court to the admissibility of evidence about a complainer’s credibility and prior sexual behaviour compatible with the accused’s right to a fair trial under article 6 of the European Convention on Human Rights (ECHR), read with article 6(3)(d)?

The appeals arose from two trials:

• Daly: A case turning on mutual corroboration between two complainers (Moorov) where the defence contended that a post-disclosure allegation by the first complainer (that she had been raped by Daly at age 13 and had borne a child) was false and should have been available to test credibility. No section 275 application was made at trial because, on existing case law, it was considered hopeless.
• Keir: A rape case where the Crown deserted charges relating to earlier sexual activity that same night, leaving a charge focused on alleged assault/rape at the accused’s home when the complainer was asleep or incapable. The defence sought to admit evidence (much of it captured on CCTV) of flirtation and consensual intimacy earlier that evening to contextualise or bear on consent/capacity and credibility. The section 275 application was largely refused as collateral/irrelevant.

The Supreme Court was assisted by interventions from the Law Society of Scotland, the Faculty of Advocates and Rape Crisis Scotland, reflecting the wider public importance and the differing perspectives of accused persons, the defence profession, and complainers.

The Court ultimately dismissed both appeals on their facts, but issued authoritative guidance of general application: the recent Scottish line of authority that treats much credibility and prior sexual behaviour evidence as “collateral” and therefore inadmissible unless “instantly verifiable” is liable to breach article 6 and must be modified. Trial courts must apply the statutory scheme of sections 274–275 of the 1995 Act as a balanced, case-by-case gatekeeping framework.

Summary of the Judgment

• Scope of appeal: Under section 288AA, the Supreme Court’s powers extend only to determining the Convention compatibility issue; the case is otherwise remitted to the High Court of Justiciary.
• Charging decisions: The Crown’s choices about charges/dockets do not per se cause unfairness; the defence remains able (and must be allowed) to seek admission of relevant evidence via section 275. The fairness question therefore turns on evidential rulings, not charge-framing alone.
• Core holding on Scots law: The Appeal Court’s modern approach—exemplified by cases such as CJM v HMA, LL v HMA, JW, CH, and practice notes—has become overly restrictive. It conflates “collateral” with “irrelevant,” demands “instant verifiability,” and treats prior sexual behaviour and credibility lines as presumptively inadmissible. That approach is liable to violate article 6 because in sexual offence trials the complainer’s credibility is often decisive; the defence must have a fair opportunity to challenge it, subject to proportionate safeguards.
• Restated approach: Sections 274 and 275 are a “careful and nuanced” statutory scheme. Courts must:
  • recognise the broad concept of relevance (including evidence bearing on credibility and necessary context);
  • assess whether the evidence is capable of strengthening the defence or undermining the prosecution in a material way;
  • conduct the section 275(1)(c) balancing exercise, weighing significant probative value against risks to the proper administration of justice, including appropriate protection of dignity and privacy (section 275(2)).
• Article 6 anchoring: The Court relies on ECtHR authority—Murtazaliyeva v Russia (defence must be able to call evidence reasonably expected to strengthen its position) and Poropat v Slovenia (refusal in principle to admit credibility evidence can render a trial unfair)—and endorses the rationale in R v A (No 2) and R v Seaboyer that rigid exclusions of relevant evidence endanger fair trials.
• Outcome in Daly: Although the general approach must change, the particular “false allegation at 13” line was too remote, would require a substantial trial-within-a-trial, and lacked clear proof of falsity; the defence had other means to challenge credibility. No article 6 violation on the facts.
• Outcome in Keir: Even assuming greater latitude generally, the excluded earlier-evening sexual conduct had very limited probative force on the key issues (sleep/incapacity and immediate non-consent), given the agreed high blood-alcohol level on arrival and the nature of the competing accounts. The trial remained fair.

Analysis

Precedents Cited and How They Shaped the Decision

The judgment maps a long arc of authorities:

• Classical Scots law on relevance and collateral issues: A v B (1895) and Moorov v HMA (1930) recognised that collateral issues may be excluded to prevent disproportionate diversion, but that credibility may be tested in cross-examination. Thomson v HMA [2010] reaffirmed that excluding collateral evidence is “subject always to the interests of justice,” a qualification largely missing from recent Appeal Court practice.
• Sexual offences and character: Dickie v HMA (1897) allowed limited bad character evidence and evidence of prior relations with the accused, recognising that the state of the relationship can bear on consent.
• Statutory reforms and early case law:
  • Scotland’s ss 274–275 (as reworked by the Sexual Offences (Procedure and Evidence) (Scotland) Act 2002) were designed as a balancing exercise, influenced by R v Seaboyer (SCC) and cognate English experience with s 41 YJCEA 1999.
  • Moir (No 1) (2005) and DS v HMA (PC, 2007) described the scheme as protecting complainers while preserving fair-trial rights; terms in ss 274–275 must be read compatibly with article 6.
• Recent Scottish line narrowed admissibility:
  • CJM v HMA [2013] recast credibility-only evidence as “irrelevant” and “collateral” unless instantly verifiable (e.g. by extract conviction), minimizing the s 275 balancing role. Lord Clarke’s concurring critique foresaw fairness dangers.
  • LL v HMA [2018], HMA v JW [2020], CH v HMA [2020], and Javaid (2024) often treated prior sexual behaviour as either irrelevant or too “collateral,” equating contemporaneity of consent with evidential irrelevance of earlier conduct, and rejecting “background/context” unless independently deemed relevant on a narrow view. Lord Malcolm and Lord Glennie cautioned against this rigidity.
• English and Canadian comparators:
  • R v A (No 2) [2002] 1 AC 45 held that past sexual relations may, depending on circumstances, illuminate the complainant’s state of mind on the occasion, and that excluding such evidence can endanger a fair trial. The House of Lords stressed logic and common sense: evidence need not prove the issue; it must have a tendency to make it more or less probable.
  • R v Martin and R v F show how credibility-related evidence can be admissible where it underpins a defence theory (e.g., motive to fabricate) or bears on the facts in issue.
  • R v Seaboyer condemned blanket exclusions that keep the fact-finder from truth absent a clear, proportionate policy justification; the fair-trial right takes precedence where conflict is unavoidable.
• Article 6 jurisprudence:
  • Murtazaliyeva v Russia (GC) refined the standard: defence must be able to call evidence that can reasonably be expected to strengthen its position; courts must give reasons and ensure overall fairness.
  • Poropat v Slovenia found a violation where courts refused, as a matter of principle, credibility evidence in a case turning on the complainant’s word.
  • Judge v UK approved the Scottish statutory scheme as then applied—precisely because it allowed admission of relevant and probative sexual history/bad character evidence under judicial control.
  • Article 8 cases (SN v Sweden, Y v Slovenia, JL v Italy) underline that victim-protective measures are legitimate but must be reconciled with effective defence rights.

Legal Reasoning

The Supreme Court’s reasoning operates on three planes: conceptual, statutory, and Convention-based.

1) Conceptual: Relevance versus “Collateral”

The Court restores the classical understanding that “collateral” describes a subset of relevant evidence that may nonetheless be excluded to prevent trials being overwhelmed or juries distracted. Recent case law had conflated “collateral” with “irrelevant,” collapsing the category of relevant credibility evidence and thereby obscuring the necessary balancing stage. The Court stresses:

• Evidence going solely to credibility can be relevant (Walker & Walker; Thomson).
• In sexual offence cases, where the complainer’s credibility often decides the outcome, the line between credibility and the facts in issue can “reduce to vanishing point” (Cross on Evidence; cited by Lord Clarke and English authority).

2) Statutory: Sections 274–275 as a Unified, Balanced Gatekeeping Scheme

Section 274’s prohibitions must be read together with section 275’s permission to admit such evidence where:

• it relates to specific occurrences/facts (s 275(1)(a));
• is relevant to establishing guilt (s 275(1)(b))—a notion that includes credibility and necessary context in sexual offence trials; and
• has significant probative value likely to outweigh prejudice to the proper administration of justice, which expressly includes protection of dignity/privacy and ensuring the jury hears facts commensurate with the issue’s importance (s 275(1)(c), (2)).

Two corollaries follow:

• The legislature anticipated that evidence about bad character, other behaviour going to credibility, and prior sexual behaviour might be admissible where probative and necessary for fairness. To treat almost all such evidence as inadmissible at common law makes the statutory scheme largely redundant—contrary to Moir (No 1), DS v HMA, and Judge v UK.
• “Instant verifiability” is not the statutory test. The statutory test is a nuanced balancing of probative value and prejudice to the administration of justice. Section 275C likewise presupposes that credibility-only evidence may be admitted (else there would be nothing for expert rebuttal to address).

3) Convention: Article 6 Demands a Nuanced Approach

Rigid exclusionary rules that prevent an accused calling or eliciting evidence reasonably expected to strengthen the defence are incompatible with article 6. The Court’s reliance on Murtazaliyeva and Poropat is decisive. In sexual offence cases:

• Evidence of prior sexual behaviour between the parties may be relevant—not to prove consent by “past behaviour,” but because it can support an inference about the complainer’s state of mind or the plausibility of the defence account in the specific circumstances (R v A (No 2)).
• The proposition “consent must be contemporaneous” is legally correct, but it does not follow that earlier expressions of willingness, or later consensual intimacy, are irrelevant. As Lord Reed makes clear, that is a non sequitur; such evidence can have probative value without constituting consent-in-advance.
• Victim-protection (article 8) remains vital, but cannot override fair-trial guarantees. Where probative value is significant, the solution is careful judicial control and directions, not blanket exclusion.

Impact

The decision has immediate and systemic consequences.

1) For Trial Judges and Gatekeeping

• Abandon the “collateral unless instantly verifiable” constraint as a controlling principle.
• Apply section 275 on its own terms, recognising that:
  • credibility and context evidence can be “relevant to establishing whether the accused is guilty,” particularly where the case turns on the complainer’s testimony;
  • the balancing test is genuine and fact-sensitive; and
  • protective measures (ground rules, pre-recorded evidence, exclusion of public, judicial directions) can mitigate prejudice where probative value is significant.
• Give clear reasons addressing:
  • logical relevance (how the evidence could strengthen the defence or undermine the Crown);
  • its probative significance (timing, specificity, connection to the disputed event, availability of objective corroboration such as CCTV or messages);
  • countervailing risks (privacy, potential to inflame prejudice, trial length), and why those risks cannot be sufficiently mitigated.

2) For Practitioners

• Defence: Section 275 applications should be precise and evidence-led, explaining the “meaningful connection” to the live issue(s), and why the material strengthens the defence case in a way not otherwise achievable.
• Crown: Oppose only where probative value is weak or where prejudice cannot be mitigated; anticipate that “context/background” may sometimes be necessary for the jury to evaluate accounts fairly; continue to seek protective measures consistent with article 6.
• Both sides: Expect more rigorous case management and earlier judicial engagement on scope, measures, and directions; consider the implications of section 275A (possible disclosure of the accused’s prior relevant convictions) whenever seeking to admit section 275 evidence.

3) For the Appeal Court and Existing Doctrine

• While the Supreme Court does not formally overrule earlier Scottish authorities (its public law function here is confined to compatibility), it disapproves the restrictive approach exemplified by CJM, LL, JW, CH, Javaid where they deny the place for section 275’s balancing and mischaracterise relevance. Future applications must adhere to the UKSC’s articulation.
• Bench Books and practice directions will require revision to reflect that:
  • credibility-only evidence can be relevant and sometimes admissible;
  • prior sexual behaviour may, in contextualised circumstances, be relevant to consent or belief in consent; and
  • “contemporaneous consent” is a concept of legal sufficiency, not an evidential gate barring logically probative earlier or later conduct.

4) Wider System

• Short-term: more section 275 applications; more detailed written reasoning; some additional trial time devoted to tightly managed collateral inquiries.
• Medium-term: better-calibrated rulings should reduce unfairness risk and align Scottish practice with ECHR and comparative common law, improving the legitimacy of outcomes.

Complex Concepts Simplified

• Compatibility issue (s 288ZA/288AA): A question whether a public authority (including a court) acted incompatibly with Convention rights. The Supreme Court can decide only that question and must remit the case.
• Collateral evidence: Evidence relevant to the case but relating to side-issues that could unduly prolong or distract. It is not the same as “irrelevant” evidence. It may be excluded, but only after balancing fairness and efficiency.
• Sections 274–275 (Scotland): s 274 sets presumptive prohibitions on admitting certain categories (sexual history, bad character, certain behaviour); s 275 allows admission if (a) the evidence is specific, (b) relevant to guilt, and (c) has significant probative value outweighing prejudice to the proper administration of justice, including dignity/privacy.
• Section 275A: If section 275 evidence is admitted, the accused’s previous relevant convictions (typically for sexual offences) may be placed before the jury unless excluded in the interests of justice. This is part of the balancing ecosystem.
• Consent must be contemporaneous: True as a legal rule. But it does not mean that earlier expressions of willingness (or later consensual intimacy) are evidentially irrelevant. Past or subsequent behaviour can still help a jury assess whether consent was present at the material time.
• Murtazaliyeva test: The defence should be able to call or elicit evidence reasonably expected to strengthen its position; courts must consider relevance and fairness and give reasons.
• Poropat principle: In a case hinging on credibility, a blanket or “in principle” refusal to hear credibility evidence can deprive the accused of a fair opportunity to defend himself.
• “Background/context” evidence: Sometimes necessary so the jury can make sense of the parties’ accounts; admissibility depends on genuine probative connection and proportionality.

Application to the Two Appeals

Daly

The defence argued that a separate allegation by the first complainer (that Daly raped her at age 13 leading to pregnancy/childbirth) should have been available to test credibility. The Supreme Court accepted the general point that credibility-only evidence may be relevant and sometimes essential. But on the specific facts: the alleged falsity was unclear, the matter was temporally and contextually distinct from the charges, and proving or disproving it would require a disproportionate inquiry tantamount to a new charge. The defence was not prevented from mounting a robust credibility challenge by other means. No article 6 breach.

Keir

The defence sought to rely on earlier-evening flirtation and intimacy (including CCTV) to support a consent/reasonable belief defence to sexual acts later at Keir’s home. The Court accepted that such evidence can be relevant in principle. However, on these facts the live issue (sleep/incapacity and immediate non-consent) was poorly illuminated by prior public-house intimacy; agreed toxicology and CCTV of severe intoxication at arrival undermined its probative value. The trial contained adequate safeguards, and excluding this limited-value material did not render the proceedings unfair. No article 6 breach.

What This Judgment Does—and Does Not—Change

• Does:
  • Repudiate the rigid “collateral = irrelevant unless instantly verifiable” approach as inconsistent with article 6.
  • Require courts to apply the section 275 balancing test genuinely, acknowledging that credibility and necessary context may be relevant and sometimes essential.
  • Clarify that “contemporaneous consent” does not preclude the relevance of earlier (or later) conduct where it has logical probative force.
• Does not:
  • License general trawls of sexual history or character. The ordinary constraints of specificity, connection, proportionality, and dignity/privacy remain.
  • Mandate admission of weak or tangential lines that risk prejudicing the fact-finding process.
  • Displace protective measures for complainers; rather, it insists on proportionate, Convention-compliant safeguards.

Practical Framework for Section 275 Applications Post-Daly/Keir

1. Identify the live issue(s): consent, incapacity, credibility, motive to fabricate, context necessary to understand accounts, belief in consent.
2. Articulate the logical connection: explain how the proposed evidence could strengthen the defence or undermine the prosecution (timing, nature, and specificity of conduct; objective anchors such as CCTV, messages, or third-party evidence).
3. Address specificity: tie the application to “specific occurrences or facts” and the inferences sought (as required by section 275(3)).
4. Assess probative value: is it significant, not marginal? Will it realistically assist the jury on the live issue?
5. Weigh prejudice to the proper administration of justice: dignity/privacy; risk of moral stereotyping; trial manageability; potential to mislead. Consider whether targeted measures (limiting scope, directions, sequencing evidence, ground rules) can adequately mitigate risk.
6. Reasoned ruling: judges should record how each limb of section 275(1) and (2) has been applied, mindful of article 6 and the guidance in Murtazaliyeva and Poropat.
7. Section 275A implications: if evidence is admitted, consider in advance how any prior relevant convictions of the accused will be handled, including possible exclusion “in the interests of justice.”

Conclusion

Daly v HMA & Keir v HMA [2025] UKSC 38 is a pivotal correction to the trajectory of Scottish evidential practice in sexual offence trials. The Supreme Court endorses the legislature’s original settlement in sections 274–275: a careful and nuanced scheme that protects complainers while preserving the accused’s right to a fair trial. The Court firmly signals that blanket or near-blanket exclusionary approaches—especially those rebranding credibility evidence as “irrelevant”—are liable to contravene article 6. What is required is a principled, transparent balancing of significant probative value against prejudice to the administration of justice, with a readiness to adopt protective measures rather than to default to exclusion.

On the facts, neither Daly nor Keir met the threshold for a Convention breach. But the systemic message is unmistakable: Scottish courts must modify their approach to ensure compatibility with article 6. In future, section 275 applications should be argued and decided on logic, common sense, and proportionality, not on rigid heuristics. The credibility of the criminal process in some of its most sensitive cases depends on striking this balance—robustly protecting complainers from needless intrusion while preserving the fairness essential to preventing wrongful conviction.