What has become known as the ‘Horizon IT Scandal’ involves a dispute, between Post Office and a group of Postmasters, which took place over many years. It primarily concerned the reliability of the Horizon computer system used in post offices and issues related to Postmasters’ contracts and the culture of Post Office at the time.

The ‘Horizon IT Scandal’ involves events which took place over many years, concerning the reliability of Post Office’s computer system, Horizon, issues related to contracts with postmasters and the culture of Post Office at the time. Many postmasters were wrongly held responsible for losses in their branch accounts that they could not explain, with some losing their livelihoods. There were also wrongful prosecutions and convictions for theft, fraud and false accounting, based on unreliable Horizon data. We are sincerely sorry for the devastating impact on so many lives and the priority of today’s Post Office is to ensure that victims receive justice and financial redress as swiftly as possible. 

The Horizon computer system is used in post offices to manage in-branch sales, with accounts being automated in the background. Previous versions of the system were found by the High Court in 2019 to have had bugs, errors and defects that could have caused shortfalls in Postmasters’ branch accounts. The High Court was also critical of Post Office’s past behaviours towards postmasters, and its Judgment also changed the way in which Post Office’s contracts with postmasters operate.

The High Court judgments, which followed civil litigation under a Group Litigation Order (GLO), can be found on the links below:

  • The Common Issues Judgment (March 2019) which determined the legal construction of the contract between Post Office and Postmasters.
  • The Horizon Issues Judgment (December 2019) which related to generic technical matters about the computer system since the original version was introduced in 1999.

The Group Litigation concluded after a jointly agreed settlement deed in 2019.

In 2020, several months after the Horizon Issues Judgment, appeals of criminal cases in which Post Office had acted as prosecutor began through the criminal courts. 

An independent Public Inquiry into the Horizon IT scandal was established in September 2020. Following a request from its Chair, Sir Wyn Williams, it became a statutory inquiry in June 2021. Post Office is fully participating to assist its work to get to the truth of what happened. More information on the Inquiry, including how to watch the hearings, is available on its website.



*Page updated 24 April 2024