Factual and Procedural Background
These appeals arise from the convictions of six former sub-postmasters ("SPMs") for offences of dishonesty occurring between 2004 and 2013. Post Office Limited ("POL") operated a computerised accounting system called Horizon, comprising two versions: Legacy Horizon (2000-2010) and Horizon Online (post-2010). Evidence of shortfalls in branch accounts generated by Horizon was central to the investigations and prosecutions of the appellants. Prior to a 2019 judgment in England and Wales, POL maintained Horizon was robust and reliable, but this was later discredited, revealing systemic problems with the system.
The Scottish Criminal Cases Review Commission ("SCCRC") began investigating Scottish prosecutions of sub-postmasters in 2020, identifying over 80 individuals potentially affected by Horizon-related issues. The SCCRC referred six convictions to the court in November 2022. Following extensive investigations, the Crown conceded each appeal, and the court allowed all appeals between September 2023 and February 2024. The court provided detailed reasons for each appeal and the factors influencing the Crown's concessions.
Legal Issues Presented
- Whether convictions based on evidence from the Horizon system were safe, given the system's unreliability.
- Whether failure by Post Office Limited and the Crown to disclose problems with Horizon constituted an abuse of process or oppressive prosecution.
- Whether pleas of guilty tendered by appellants were made under prejudicial or unfair circumstances, including consideration of Article 6 ECHR rights to a fair trial.
- Whether new evidence about Horizon's unreliability justified quashing convictions.
Arguments of the Parties
Appellants' Arguments
- The appellants contended that the Horizon system was inherently unreliable and that prosecutions relying on its data were unsafe.
- Some appellants argued their guilty pleas were made under duress or without full knowledge of Horizon's flaws, rendering the pleas prejudicial and unfair.
- They maintained that failures in disclosure by POL and the Crown deprived them of the opportunity to challenge the evidence effectively.
- Claims of oppression were advanced on the basis that prosecutions were tainted by systemic unfairness due to reliance on defective Horizon data.
- Fresh evidence about Horizon's defects, unavailable at trial, was relied upon to support appeals.
Crown's Arguments
- The Crown accepted that cases where Horizon evidence was essential to conviction ("Horizon cases") could not be supported, as the evidence was unreliable and disclosure failures prevented fair trials.
- In some cases, the Crown conceded the appeals on public interest grounds even if not strictly Horizon cases.
- The Crown acknowledged that admissions by appellants were often ambiguous, made under pressure, or based on unreliable evidence.
- The Crown highlighted systemic failures by POL, including inadequate record-keeping, lack of dispute resolution mechanisms, and suppression of evidence regarding Horizon's faults.
- The Crown relied on a joint minute of agreement with appellants' agents outlining general facts about Horizon's unreliability and POL's conduct during the relevant period.
Table of Precedents Cited
| Precedent |
Rule or Principle Cited For |
Application by the Court |
| Alan Bates & Ors v Post Office Limited (No. 6) [2019] EWHC 3408 (QB) |
Establishing that Horizon was not robust and had systemic defects. |
Used to demonstrate that reliance on Horizon evidence was misplaced and undermined convictions. |
| Josephine Hamilton & Ors v Post Office Limited [2021] EWCA Crim 577 |
Quashing convictions where trials were unfair due to reliance on Horizon evidence. |
Supported the view that prosecutions based on Horizon evidence were an affront to public conscience. |
| O'Donnell v Post Office Limited [2023] EWCA Crim 979 |
Recognition of significant problems with Horizon and Crown's failure in disclosure. |
Adopted as factual basis accepted by the Crown regarding Horizon's unreliability and prosecution unfairness. |
| HM Advocate v Withey 2017 JC 249 |
Definition of oppressive prosecution and miscarriage of justice. |
Applied to conclude that prosecutions relying on Horizon evidence were oppressive and unfair. |
| Healy v HM Advocate 1990 SCCR 110 |
Tests for validity of guilty pleas tendered under prejudicial circumstances. |
Referenced in assessing whether pleas were made fairly in light of nondisclosure of Horizon defects. |
| Kalyanjee v HM Advocate 2014 JC 233 |
Similar to Healy, concerning fairness of guilty pleas and disclosure obligations. |
Used to evaluate the circumstances of appellants' pleas in the context of withheld evidence. |
| Meredith v Lees 1992 JC 127 |
Corroboration of admissions and evidential reliability. |
Applied to assess the evidential value of admissions in light of unreliable Horizon data. |
| Sneddon v HM Advocate 2006 JC 41 |
Reclassification of charges where original charges could not be supported by evidence. |
Used to treat one appellant's conviction for uttering false accounts as a fraud conviction. |
Court's Reasoning and Analysis
The court analysed the appeals against the backdrop of established findings that Horizon was unreliable and that POL and the Crown failed in their disclosure duties. It accepted the Crown's concession that convictions relying essentially on Horizon evidence could not stand, as such trials were unfair and oppressive. The court considered the nature of each appellant's case, including whether the plea was tendered under prejudicial circumstances and whether admissions were freely made.
For appellants who pled guilty, the court examined the context of their pleas, noting circumstances such as ambiguous admissions, mental health difficulties, and lack of legal advice. It found that nondisclosure of Horizon's flaws deprived appellants of a fair opportunity to challenge evidence, violating Article 6 ECHR rights.
The court also accepted that in some cases, admissions relied upon as corroboration were factually inaccurate or made under pressure, further undermining the prosecution's case. The joint minute of agreement detailing POL's systemic failings, lack of dispute resolution, and suppression of evidence was a significant factor in the court's assessment.
Ultimately, the court found that all appeals should be allowed due to miscarriages of justice arising from reliance on defective Horizon evidence, failures in disclosure, and oppressive prosecution practices.
Holding and Implications
The court ALLOWED ALL APPEALS and quashed the convictions of the six appellants.
The direct effect of this decision is the overturning of convictions obtained through reliance on the unreliable Horizon system and associated prosecutorial failings. The court did not establish new legal precedent but applied established principles concerning fair trial rights, disclosure obligations, and the impact of unreliable evidence on convictions. The judgment signals the court's expectation that further similar cases referred by the SCCRC will be treated consistently, emphasizing the necessity of full disclosure and fairness in prosecutions involving complex technical evidence.