Post‑conviction psychiatric developments as fresh evidence justifying the quashing of guilty‑plea convictions; no substitution of a section 51A verdict

Case: Appeal following a reference from the Scottish Criminal Cases Review Commission by Shiva Mackison against Procurator Fiscal, Paisley

Citation: [2025] HCJAC 45 (HCA/2025/241/XC; HCA/2025/242/XC)

Court: Appeal Court, High Court of Justiciary (Scotland)

Bench: Lord Justice Clerk (Lord Beckett), Lord Matthews, Lord Armstrong

Date: 9 October 2025

Introduction

This reference appeal arises from two summary convictions recorded in December 2021 after the appellant, Ms Shiva Mackison, tendered pleas of guilty to communications offences (Communications Act 2003, section 127(1)(a)) and a breach of special bail conditions (Criminal Procedure (Scotland) Act 1995, section 27(1)(b)). All charges were aggravated as involving abuse of a partner or ex‑partner under section 1 of the Abusive Behaviour and Sexual Harm (Scotland) Act 2016.

The Scottish Criminal Cases Review Commission (SCCRC) referred the case in light of new psychiatric material showing that, at the time of the offences and pleas, the appellant suffered from a delusional disorder associated with postpartum psychosis, undermining both her criminal responsibility (section 51A of the 1995 Act) and capacity to engage effectively in criminal proceedings (section 53F). The Crown, having undertaken further inquiries (including precognition of the original psychiatrist), conceded that a miscarriage of justice occurred on each complaint. The Appeal Court was asked to quash the convictions and consider the appropriate disposal.

The appeal engages core questions about how Scottish appellate courts treat guilty pleas in the face of subsequent medical developments, what amounts to “fresh evidence” under section 106(3) of the 1995 Act, the threshold for “exceptional circumstances” when withdrawing guilty pleas, and the relationship between mental disorder defences (section 51A) and unfitness for trial (section 53F).

Summary of the Judgment

• The Court accepted the Crown’s concession that there had been a miscarriage of justice on each complaint. The decisive material was fresh psychiatric evidence, significantly informed by post‑conviction developments (notably compulsory detention and robust response to antipsychotic medication), which demonstrated that the appellant suffered from a delusional disorder at the material times.
• The Court held that, had this evidence been available at first instance, the appellant would likely have succeeded with the special defence of lack of criminal responsibility under section 51A, and the Crown would likely have accepted it. She would have been acquitted and dealt with under section 57 disposals, rather than imprisoned.
• The Court refrained from making a formal finding of unfitness for trial under section 53F because the material before it was “not particularly well focussed” against the statutory criteria, even though the Court suspected she was probably unfit at the time.
• Following Duzgun v HM Advocate, the Court declined to substitute a verdict on the special defence or to make a section 57 disposal. Instead, it simply quashed the convictions on both complaints. The Crown did not seek authority for a new prosecution.
• The Court reaffirmed that post‑trial clinical trajectory and treatment response can be crucial fresh evidence in differentiating psychotic illness from personality disorder (Reid and Jackson), and that exceptional circumstances can justify withdrawing guilty pleas where those pleas were entered under real error or misconception (Healy; McGarry).

Detailed Analysis

1) Statutory Framework

• Section 106(3) (1995 Act): Appeals may be founded on a miscarriage of justice that includes fresh evidence not heard at the original proceedings, provided there is a reasonable explanation for its earlier absence (section 106(3A)).
• Section 51A (Lack of criminal responsibility): An accused is not criminally responsible if, at the time, they were unable, by reason of mental disorder, to appreciate the nature or wrongfulness of conduct. It is a special defence to be established on a balance of probabilities by the accused. Pure personality disorder does not suffice.
• Section 53F (Unfitness for trial): A person is unfit if incapable, due to mental or physical condition, of participating effectively in a trial, assessed by abilities including understanding the charge and trial process, evidence, and ability to instruct lawyers.
• Section 57: Disposals available after an acquittal by reason of mental disorder (e.g., compulsion order).
• Section 190: Appeal powers in summary proceedings (disposal powers parallel to section 118 in solemn cases), relevant to whether the court may substitute a verdict on a special defence.

2) Factual and Procedural Matrix

The appellant pled guilty in December 2021 to abusive electronic communications directed at her husband (29 June and 8 October 2021) and to breaching special bail conditions (13 October 2021). A pre‑sentencing psychiatric report by Dr Karen Bett (14 February 2022) concluded there was no evidence of psychosis, diagnosing mild to moderate depression with possible paranoid personality traits. She was sentenced in March 2022 to total short custodial terms. Notably, a court request for a local psychiatric report (Douglas Inch Centre) appears never to have been pursued.

After release, the appellant’s mental state further deteriorated. She was compulsorily detained in November 2022 and treated with olanzapine, responding significantly. The Mental Health Tribunal (January 2023) made findings consistent with delusional disorder and absence of insight, with a five‑year history of persecutory beliefs against the husband and family. The husband corroborated long‑standing concerns and had previously flagged deterioration to the Procurator Fiscal. The SCCRC commissioned Professor John Crichton (forensic psychiatrist), who—having access to full multi‑disciplinary records and collateral history—diagnosed delusional disorder arising postpartum, with impaired appreciation of wrongfulness at the material times. He considered the appellant likely unable to participate effectively around the time of first instance proceedings.

The Crown, upon precognoscing Dr Bett, learned she did not have access to GP records, social work records, productions (emails/messages), or the husband’s collateral account, and was unaware of an Adult Support and Protection meeting noting fixed false beliefs (delusional disorder) in January 2022. The Crown conceded that the circumstances of the pleas were exceptional and clearly prejudicial to the appellant and that a miscarriage of justice had occurred.

3) Precedents Cited and Their Influence

• Reid v HM Advocate [2012] HCJAC 150, 2013 SCCR 70: Endorsed reliance on longitudinal assessment and treatment response to differentiate psychotic illness from personality disorder, and acknowledged that accurate diagnosis may not be possible from limited or short‑term examinations. This underpins the Court’s willingness to treat post‑conviction improvement on antipsychotics as probative of psychosis at the earlier time.
• Jackson v HM Advocate 1998 SCCR 539 (Lord Coulsfield): Quoted in Reid; emphasises that mental illness diagnosis benefits from observing response to treatment over time. The Court drew on this principle to regard the appellant’s marked improvement on olanzapine as powerful fresh evidence.
• Daly v HM Advocate (unreported, 14 May 1997): Conviction quashed on fresh evidence where post‑trial illness and response to antipsychotics undermined the original finding that the accused had feigned illness. The case supports using post‑trial psychiatric developments to reassess earlier mental state and culpability.
• Healy v HM Advocate 1990 SCCR 110: Established that withdrawal of a guilty plea requires exceptional circumstances—i.e., the plea was tendered under a real error or misconception or in clearly prejudicial circumstances. The Court applied this through later authority.
• McGarry v HM Advocate [2022] HCJAC 18, 2022 JC 148: Reaffirmed Healy’s “exceptional circumstances” test in the guilty‑plea context. The Court used McGarry to frame the standard for allowing guilty pleas effectively to be set aside on appeal where fresh psychiatric material reveals prejudice or misconception.
• Duzgun v HM Advocate [2020] HCJAC 13, 2020 JC 183: Addressed the Appeal Court’s disposal powers and the impropriety of substituting a verdict on the special defence and imposing a mental health disposal on appeal after guilty pleas. Guided this Court’s refusal to substitute an acquittal by reason of section 51A and to make a section 57 order; the Court instead limited itself to quashing the convictions.

4) The Court’s Legal Reasoning

• Fresh evidence and reasonable explanation (section 106(3), (3A)):
  • The post‑conviction period involved compulsory treatment and a marked clinical response to antipsychotics—developments that could not have been known at the time of the original proceedings and which materially altered the diagnostic picture.
  • There was a reasonable explanation for the earlier absence of the evidence: the initial psychiatrist lacked comprehensive records and collateral accounts; the appellant’s presentation masked her psychosis; potentially critical collateral information (from the husband and ASP meeting) was not integrated into first‑instance assessment.
• Exceptional circumstances justifying the setting aside of guilty pleas (Healy; McGarry):
  • The pleas were tendered under a real error or misconception as to the nature and legal implications of the appellant’s mental disorder. On the accepted fresh evidence, she had a section 51A defence and probably lacked capacity to instruct and participate effectively.
  • Those circumstances were “clearly prejudicial” to the appellant: she served custodial sentences when, on the Crown’s position, she bore no criminal responsibility.
• Lack of criminal responsibility (section 51A):
  • With the benefit of longitudinal data and treatment response, Professor Crichton concluded the appellant was unable, by reason of mental disorder (delusional disorder associated with postpartum psychosis), to appreciate the nature or wrongfulness of her conduct at the time of the offences.
  • The court accepted that, had this been available, the special defence would likely have succeeded and the Crown would likely have accepted it. The Court noted the statutory exclusion of pure personality disorder and accepted that the clinical story (including marked response to antipsychotics) effectively ruled that out as the sole explanation.
• Unfitness for trial (section 53F):
  • The Court suspected the appellant was unfit for trial at the time, but declined to make a formal finding because the appeal materials were not sufficiently aligned to the section 53F criteria. This underscores that unfitness is a structured, functional test tied to specific abilities and must be precisely addressed.
• Disposal and limits on substituting verdicts (Duzgun; sections 118/190 and 57):
  • While quashing for fresh evidence often prompts authorisation of a new prosecution, the Crown did not seek this. Following Duzgun, the Court held it was not appropriate to substitute a special defence verdict or impose a mental health disposal under section 57 on appeal. The proper course was to quash the convictions.

5) The Role of Post‑Conviction Developments as Fresh Evidence

This decision consolidates a line of authority (Reid, Jackson, Daly) recognising that psychiatric diagnosis may only crystallise over time, especially where response to antipsychotics is revealing. Post‑trial events—compulsory detention, independent tribunal findings of delusional disorder, and consistent recovery on antipsychotics—were decisive in establishing that the appellant’s earlier culpability assessment was wrong. The Court expressly treated these developments as the “most compelling aspect” of the appeal.

6) Procedural Oversights and Systemic Lessons

• Incomplete psychiatric information at first instance: The original psychiatric report lacked access to key records (GP, social work, productions) and collateral history (husband). This materially impaired diagnostic accuracy.
• Unfollowed court request: A request to a local psychiatric service (Douglas Inch Centre) appears not to have been pursued, missing an opportunity for an integrated assessment with local records and collateral interviews.
• Collateral information matters: The husband had repeatedly flagged deterioration; an Adult Support and Protection meeting identified “fixed false beliefs.” Collateral synthesis across agencies is critical where psychosis is suspected.
• Masking and insight: The appellant’s ability to conceal symptoms and her lack of insight complicated assessment—a known phenomenon in delusional disorders—which heightens the need for multi‑source verification.

Impact and Implications

A) Appellate practice

• Guilty pleas are not an absolute bar: Where fresh psychiatric evidence provides a reasonable explanation for its absence at trial and shows exceptional, prejudicial circumstances, convictions based on guilty pleas can be quashed.
• Post‑trial clinical trajectory is probative: Compulsory treatment, tribunal findings, and robust response to antipsychotics can carry decisive weight in establishing a historical psychosis and rebutting personality disorder.
• Disposal constraints: Following Duzgun, the Appeal Court will be slow to substitute a special defence verdict or impose section 57 disposals after quashing. The usual remedy is to quash; authority for retrial is a matter for the Crown to seek.

B) Trial practice and case preparation

• Early, comprehensive psychiatric inquiry: Defence and Crown should seek reports from clinicians with access to full GP, social work, police productions, and collateral interviews. Where local records are key, local services should be engaged.
• Collateral gathering is essential: Input from family members, Adult Support and Protection processes, and multi‑agency records should be systematically obtained and synthesised where mental disorder is suspected.
• Fitness for trial must be properly framed: Courts and practitioners should assess section 53F using the statutory functional criteria; general impressions of vulnerability are insufficient.
• Beware masking and insight issues: A lack of overt psychotic symptoms or a patient’s denial of illness should not end inquiry where collateral suggests delusional beliefs.

C) Substantive mental disorder defences

• Section 51A focus on appreciation of wrongfulness: Delusional disorder may negate appreciation of wrongfulness even where outward presentation is superficially organised.
• Personality disorder exclusion: The Court endorsed using treatment response to distinguish psychosis from personality disorder; rapid improvement with antipsychotics weighed against personality disorder as the sole explanation.

D) Domestic abuse context

While the charges were aggravated as partner abuse, the Court did not dilute the stringent standards for mental disorder defences. The ruling underscores that serious domestic abuse contexts do not preclude acquittal by reason of mental disorder where the statutory test is met. The Crown’s approach demonstrates that public interest in domestic abuse prosecutions co‑exists with fairness in recognising genuine lack of criminal responsibility.

Complex Concepts Simplified

• Fresh evidence (section 106(3)): New evidence significant to the case that was not available at the original proceedings. There must be a reasonable explanation for why it was not heard then. Post‑conviction medical developments can qualify.
• Withdrawing/setting aside guilty pleas: The Appeal Court can quash convictions entered on guilty pleas in exceptional circumstances—where the plea was tendered under error/misconception or in circumstances clearly prejudicial to the accused.
• Section 51A—lack of criminal responsibility: If, because of mental disorder, the accused could not appreciate the nature or wrongfulness of their conduct at the time, they must be acquitted. The accused must prove this on the balance of probabilities. Pure personality disorder does not suffice.
• Section 53F—unfitness for trial: This is about the accused’s present ability (at the time of trial) to participate effectively—understanding charges, proceedings, evidence, and being able to instruct lawyers. It is different from section 51A, which concerns mental state at the time of the offence.
• Compulsory Treatment Order (CTO): A civil mental health measure authorising treatment and, sometimes, detention. Tribunal findings and CTO history can be powerful evidence of serious mental disorder.
• Section 57 disposals: If acquitted by reason of mental disorder, the court may impose mental health disposals (e.g., compulsion order). On appeal after guilty pleas, the Court generally will not substitute such a verdict/disposal (Duzgun).

What the Court Did Not Decide

• No formal finding of unfitness (section 53F): The Court suspected unfitness but declined to decide without evidence squarely aligned to the statutory criteria.
• No substituted special defence verdict/disposal: The Court did not acquit by reason of section 51A or impose section 57 measures; it simply quashed the convictions.
• No authorisation for retrial: The Crown did not seek authority for a fresh prosecution; the Court therefore did not address that course.

Practical Takeaways for Practitioners

• Where mental disorder is in play, insist on reports that integrate:
  • Full GP and psychiatric records;
  • Social work and Adult Support and Protection records;
  • Police productions and communications;
  • Collateral interviews (especially close family/complainers); and
  • Longitudinal clinical data and, where possible, treatment response.
• Frame fitness for trial arguments using the explicit section 53F abilities; avoid generic assertions.
• In plea discussions, ensure any potential section 51A defence is fully investigated; record reasons if not advanced.
• For the Crown, where a later psychiatric picture changes culpability assessment, be prepared to concede miscarriage and consider whether to seek authority for retrial.

Conclusion

Mackison reaffirms and sharpens a vital appellate principle in Scottish criminal law: robust post‑conviction psychiatric developments—especially compulsory treatment coupled with clear response to antipsychotics—can constitute fresh evidence that not only explains earlier diagnostic uncertainty but also compels the conclusion that a guilty plea was tendered under error or in prejudicial circumstances. In such cases, exceptional circumstances justify setting aside the plea and quashing the conviction.

The Court carefully distinguishes between suspicion of unfitness and the need for evidence mapped precisely onto section 53F criteria, while recognising that the same body of psychiatric material could have supported a section 51A defence at trial. Following Duzgun, it also clarifies that the appropriate appellate remedy in this scenario is to quash convictions rather than to substitute a special defence verdict and impose mental health disposals.

Beyond this case, the judgment underscores the systemic importance of comprehensive, multi‑source psychiatric assessment at first instance; proactive gathering of collateral information; and vigilance against the masking effects of psychosis. It will influence future appeals involving mental disorder, guilty pleas, and fresh evidence, and it offers practical guidance to defence, prosecution, and courts on aligning clinical realities with legal standards of culpability and trial fitness.