Draft:Post Office Horizon IT Inquiry

• Comment: In preparing this draft, I disclose that AI assistance was used as follows: https://share.gemini.google/VHKu68tZDBYd Smithr32 (talk) 11:47, 2 October 2026 (UTC)

Post Office Horizon IT Inquiry

Part of British Post Office scandal
Fujitsu headquarters Sir Alan Bates
Date	September 2020 (non-statutory) 1 June 2021 (2021-06-01) (statutory)
Location	United Kingdom
Type	Public inquiry
Organised by	Government of the United Kingdom
Website	Official website

The Post Office Horizon IT Inquiry is a public inquiry in the United Kingdom into the implementation and operation of the Horizon accounting system, and the actions taken by Post Office Ltd and others in response to apparent financial shortfalls recorded by the system. The inquiry was established on a non-statutory basis in September 2020 and was converted into a statutory inquiry under the Inquiries Act 2005 on 1 June 2021, with Sir Wyn Williams as chair.

The inquiry examined the development and operation of Horizon, the use of information generated by the system in investigations and prosecutions, the treatment of postmasters, compensation and access to justice, and the governance and oversight of the Post Office and its relationship with government. Its work was divided into seven phases. Public hearings began in February 2022 and concluded with closing submissions in December 2024.

The first volume of the chair's final report was published on 8 July 2025 and dealt with the human impact of the scandal and financial redress. It contained 19 recommendations. As of July 2026, five further volumes remained in preparation; Sir Wyn Williams said that these would cover the period from the development of Legacy Horizon to events after the end of the litigation brought by Alan Bates and other claimants against the Post Office.

Background

Main articles: British Post Office scandal and Horizon accounting system

The inquiry arose from the wider British Post Office scandal, in which hundreds of postmasters were prosecuted and thousands more were held financially responsible for apparent losses recorded by Horizon. The system was developed for the Post Office by Fujitsu and began to be rolled out from 1999. Postmasters had reported discrepancies in branch accounts almost from the beginning of the rollout, but the Post Office continued to rely on Horizon data in seeking to recover alleged shortfalls and, in England and Wales, in criminal prosecutions.

In 2009, Computer Weekly reported allegations that Horizon could generate erroneous information, while the Justice for Subpostmasters Alliance was formed to campaign on behalf of affected postmasters. Subsequent investigations, the group litigation brought by 555 postmasters, and judgments of the High Court and Court of Appeal established the basis for challenges to convictions and increased pressure for an independent inquiry.

Following the settlement of the group litigation in 2019 and the beginning of successful appeals against convictions, campaigners and parliamentarians called for a judge-led investigation into the causes of the scandal and the conduct of the Post Office and government.

Establishment

Non-statutory inquiry (2020–2021)

On 26 February 2020, the government indicated that it would establish an independent inquiry into the Horizon scandal. On 10 June 2020, the government announced an independent review of the Post Office's Horizon IT system and the use of information generated by it in criminal trials.

The review was established as a non-statutory inquiry in September 2020 under the chairmanship of Sir Wyn Williams. It issued a call for evidence on 1 December 2020, and its first public hearing took place on 15 January 2021. Two public hearings were held during the non-statutory phase, followed by a preliminary hearing on the provisional list of issues in November 2021.

The original review had a narrower remit than the later statutory inquiry. In particular, it did not include the Post Office's prosecution function, the settlement reached in the group litigation, or the conduct of current or future litigation.

Conversion to a statutory inquiry (2021)

On 19 May 2021, the government announced that the inquiry would be placed on a statutory footing. It was formally converted under the Inquiries Act 2005 on 1 June 2021, giving the chair additional powers to compel witnesses and require the production of evidence.

The statutory inquiry's terms of reference required it to establish what went wrong with Horizon and the Post Office's use of information from the system; obtain relevant evidence from the Post Office, Fujitsu, government departments and UK Government Investments; assess whether changes promised by the Post Office had been delivered; and examine governance, oversight and whistleblowing arrangements.

The terms of reference also required the inquiry to take account of the findings of the High Court in Bates & Others v Post Office Ltd and the Court of Appeal in R v Hamilton and others, as well as other judgments in which convictions had been quashed.

Scope and issues

The inquiry divided its investigation into seven phases:

1. Phase 1 – Human impact: the effects of the Horizon scandal on people adversely affected by the system.
2. Phase 2 – Horizon IT system: the procurement, design, pilot, rollout and modification of Horizon.
3. Phase 3 – Operation: training, assistance, dispute resolution, knowledge of errors and the rectification of problems.
4. Phase 4 – Action against sub-postmasters and others: policy-making, audits, investigations, civil and criminal proceedings, and failures in investigation and disclosure.
5. Phase 5 – Redress: access to justice, Second Sight, the Complaint Review and Mediation Scheme, the group litigation, responses to the scandal and compensation schemes.
6. Phase 6 – Governance: monitoring of Horizon, contractual arrangements, internal and external audit, technical competence, stakeholder engagement, oversight and whistleblowing.
7. Phase 7 – Current practice and procedure and recommendations for the future.

The inquiry also considered devolved matters in Scotland, Wales and Northern Ireland within the scope of its work.

Evidence and disclosure

The inquiry collected evidence from affected postmasters and their families, current and former employees of the Post Office and Fujitsu, lawyers, accountants, civil servants, ministers and other witnesses. Written evidence included witness statements, internal correspondence, technical material, legal documents and records relating to investigations and prosecutions.

Disclosure became a significant procedural issue during the inquiry. The chair issued a number of directions concerning late disclosure by the Post Office, including directions relating to electronic communications and other documents. There were also hearings concerning legal professional privilege and applications by the Metropolitan Police Service for restrictions on access to certain material.

The inquiry's documentary work was extensive. In 2025 alone, the inquiry said it had published more than 13,500 documents comprising more than 161,000 pages, in addition to witness statements and other material.

Phase 1: Human impact (2022)

The Phase 1 hearings opened on 14 February 2022 and examined the effects of the Horizon scandal on postmasters and their families.

The inquiry heard evidence concerning the consequences of alleged accounting shortfalls and subsequent investigations, including financial loss, disciplinary action, criminal prosecution, imprisonment, bankruptcy, damage to reputation and relationships, and physical and psychological effects. The evidence included personal accounts from those who had been prosecuted or otherwise affected by Horizon-related disputes.

The first volume of the final report subsequently placed the human impact at the forefront of the inquiry's work. In that report Sir Wyn Williams estimated that approximately 1,000 people had been prosecuted and convicted in the United Kingdom during the relevant period on the basis of Horizon evidence, while about 10,000 people were eligible for compensation through the redress schemes at the time of the report.

The report also recorded the severe consequences experienced by some affected people and linked at least 13 suicides to the scandal. It recorded 59 further people who had reported suicidal thoughts, including ten who said that they had attempted suicide.

The chair emphasised that the inquiry's human-impact material was intended to describe the suffering documented in evidence and did not, in the individual case illustrations, constitute final factual findings about every aspect of the underlying events.

Phase 2: Horizon IT system (2022)

Phase 2 examined the procurement, design, pilot, rollout and modification of the Horizon system. It also considered the involvement of Fujitsu and what was known about faults in the system by the Post Office and Fujitsu during its development and operation.

The hearings considered evidence about Legacy Horizon, which was introduced from 1999, and subsequent versions including Horizon Online. Witnesses included current and former employees involved in the system's development and operation, as well as technical experts and postmasters.

The inquiry heard evidence that Horizon was capable of producing data representing apparent gains or losses that did not necessarily correspond to real movements of money. In 2024, Paul Patterson, Fujitsu's director of European services, told the inquiry that the system had contained bugs, errors and defects from the beginning and apologised for Fujitsu's role in the scandal.

Much of the detailed technical history of Horizon is covered in the separate article Horizon accounting system.

Phase 3: Operation (2023)

Phase 3 examined how Horizon operated in practice, including the training and assistance provided to postmasters, the handling of disputes, knowledge within the Post Office of errors in the system and the steps taken to rectify them.

The hearings took place between January and March 2023.

Evidence considered by the inquiry included the treatment of reports that branch accounts did not reconcile, the response of Post Office staff to complaints, and the extent to which information about known or suspected defects was communicated to decision-makers and postmasters.

The phase also considered technical and operational questions concerning remote access to branch systems and the ability to alter data or transactions. These issues had previously been disputed in litigation and criminal cases and formed part of the inquiry's wider examination of how Horizon information was treated as evidence.

Interim report on compensation (2023)

The inquiry issued its first interim report on compensation on 17 July 2023. It made eight recommendations concerning the administration and operation of the compensation schemes.

The recommendations included:

• strengthening the role and capacity of the Horizon Compensation Advisory Board;
• requiring written reports from the board's meetings and consideration of whether compensation was full and fair;
• preventing compensation payable to bankrupt claimants from being diverted improperly through insolvency proceedings;
• clarifying the tax treatment of compensation under the different schemes;
• providing for the payment of Group Litigation Order compensation after the original deadline of August 2024 where necessary; and
• establishing arrangements for the conclusion of the Horizon Shortfall Scheme.

The government accepted the recommendations in full or in part in October 2023.

The interim report formed part of the inquiry's continuing examination of redress and was followed by further compensation hearings in 2024 and the recommendations contained in Volume 1 of the final report.

Phase 4: Action against sub-postmasters and others (2023–2024)

Phase 4 examined the actions taken against postmasters and others, including policy-making, audits, investigations, civil proceedings, criminal proceedings, disclosure and the responsibility for failures in those processes.

The hearings ran from July 2023 into January 2024.

The inquiry considered evidence about how Horizon data was used in criminal prosecutions and civil disputes, the knowledge of Post Office and Fujitsu personnel about system faults, and the handling of expert evidence.

Among the witnesses was Paul Patterson, who gave evidence about Fujitsu's knowledge of defects in Horizon. The inquiry also heard evidence from former Post Office lawyers and executives, and from people involved in earlier reviews of the system.

The phase included detailed consideration of expert evidence given by Gareth Jenkins, a Fujitsu engineer who had acted as an expert witness in prosecutions. Jenkins gave evidence to the inquiry about his understanding of Horizon and the preparation of expert statements used in legal proceedings.

Phase 4 also involved significant issues concerning disclosure. The chair issued several directions relating to late disclosure by the Post Office in 2023 and 2024.

Phases 5 and 6: Redress and governance (2024)

Phases 5 and 6 began on 9 April 2024. They examined redress and access to justice, earlier investigations by Second Sight, the Complaint Review and Mediation Scheme, the group litigation and the response to the scandal. They also examined governance, monitoring of Horizon, contractual arrangements, internal and external audit, technical competence, stakeholder engagement, oversight and whistleblowing.

Redress and access to justice

The inquiry heard evidence about the operation of the various compensation schemes established after the Horizon scandal became widely recognised. It examined issues including eligibility, assessment of claims, delays, legal advice, the role of independent panels and the treatment of different categories of claimants.

Evidence was also heard from people who had participated in earlier attempts to investigate Horizon, including representatives and investigators associated with Second Sight. The inquiry examined the history of those investigations and the relationship between the earlier review processes and the later compensation arrangements.

Governance and oversight

Phase 6 examined the governance of Post Office Ltd and its relationship with government and UK Government Investments. Witnesses included former Post Office executives and board members, government ministers and officials, and senior figures connected with Fujitsu.

Among the issues considered were the extent to which information about Horizon faults reached senior management and government, the effectiveness of internal and external audit, the organisation's approach to whistleblowing, and the way in which risks associated with the system were communicated and managed.

The inquiry also considered the handling of legal advice and the extent to which information about Horizon was passed to ministers, regulators and investigators.

Phase 7: Current practice and future recommendations (2024)

Phase 7 began on 23 September 2024 and considered current Post Office practices and procedures, as well as recommendations for the future.

The inquiry examined the operation of the Post Office after the earlier litigation and subsequent public scrutiny. Evidence included the operation of current contracts, the use of Horizon information and the arrangements governing investigations and dispute resolution.

The inquiry was told that, as recently as 2023, Post Office executives had changed data on Horizon systems used by postmasters without their knowledge. It also heard evidence concerning continuing concerns about the treatment of postmasters and the operation of the Post Office's investigatory powers.

The phase also considered the response of government and other organisations to the findings that had emerged from the scandal and the measures needed to prevent similar failures in future.

Closing of the hearings (2024)

The inquiry's public hearings concluded in December 2024. Closing statements were heard on 16 and 17 December 2024, after which the inquiry entered the Maxwellisation process before publication of the final report.

The Maxwellisation process requires individuals or organisations likely to be criticised in the report to be warned of the substance of the proposed criticism and given an opportunity to make representations before the report is finalised.

Final report

Volume 1 (2025)

The first volume of Sir Wyn Williams's final report was published on 8 July 2025. It was 162 pages long and considered the human impact of the Horizon scandal and financial redress.

The report stated that it was based on evidence and information available to the chair up to 6 June 2025. It considered the experiences of people affected by Horizon, the operation of the compensation schemes and whether financial redress had been delivered in a full, fair and prompt manner.

The report contained 19 recommendations. They included recommendations concerning the meaning of full and fair redress, access to legal advice for claimants, the assessment and appeal of compensation claims, the operation of the Horizon Shortfall Scheme, the treatment of claims under the overturned convictions and Group Litigation Order schemes, the creation of a standing public body for future redress schemes, and restorative justice.

One recommendation called for the Department, Post Office and Fujitsu to publish a report on any agreed programme of restorative justice or actions taken towards establishing such a programme by 31 October 2025.

Remaining volumes (2026–present)

Sir Wyn Williams announced in July 2026 that the remainder of his report would comprise five further volumes. He said the volumes would cover the period from the creation of Legacy Horizon to a suitable point in 2026 and would, so far as reasonably possible, follow a chronological narrative.

The chair said that Volumes 2 to 5 were closely connected and should be published together, rather than sequentially. He said Volume 6 would concern events and issues arising after the conclusion of the litigation between Alan Bates and the Post Office and should not be published before the earlier volumes.

As of 8 July 2026, the remaining report was still several months from completion. Warning letters had been sent to people and organisations criticised in Volumes 2 and 3, with further warning letters expected in relation to Volumes 4 to 6.

The inquiry therefore remained a live process after the conclusion of the public hearings, with the publication of the remaining volumes and their recommendations still outstanding.

Government response and implementation

Following publication of Volume 1, the government established a recommendations dashboard to record the recommendations of the Post Office Horizon IT Inquiry, the government's responses and progress towards implementation. The dashboard was first published on 2 March 2026 and was updated on 16 June 2026.

The inquiry's recommendations therefore became part of an ongoing process of government action and monitoring. Further recommendations are expected to arise from the remaining volumes of the final report.

Legacy project

After the conclusion of the public hearings, the inquiry began work on a legacy project intended to preserve the history of the Horizon scandal and the experiences of those affected. In 2025, the inquiry announced that it would work with The Postal Museum on part of the project.

The inquiry's listening project, In Your Own Words, continued after the hearings, allowing people affected by the scandal to submit accounts of their experiences. The inquiry said in December 2025 that 337 people had shared their stories through the project.

See also

• British Post Office scandal
• Horizon accounting system
• Bates & Others v Post Office Ltd
• Post Office (Horizon System) Offences Act 2024

External links

• Post Office Horizon IT Inquiry
• Post Office (Horizon) Inquiry recommendations dashboard – GOV.UK

References

Category:British Post Office scandal