Former Post Office chairman Tim Parker said he “regretted” following the advice of the organisation’s legal chief to keep secret a critical report that could have bolstered claims by postmasters wrongly accused of theft and false accounting.

Parker was questioned about the report at the final hearing of the public inquiry into the Post Office scandal. Like many previous witnesses, his answers often relied on the passage of time to say he could not remember certain details he was questioned about. In his 158-page witness statement, Parker used the phrase “I can’t remember” 64 times.

In 2015, he was appointed part-time chairman of the Post Office’s board of directors after allegations mounted that errors in the Post Office’s Horizon IT system had led to accounting errors blamed on postmasters.

In August 2015, the BBC published Panorama documentary had revealed more information about supplier Fujitsu having access to and redacting financial records at Post Office branches – something the Post Office had denied was possible. A month later, then-minister Baroness Lucy Neville-Rolfe asked Parker to prioritise investigating the allegations surrounding Horizon when he took up the post.

At the time, the Criminal Cases Review Commission was already reviewing a number of cases brought by sub-postmasters who had been prosecuted.

Parker assigned attorney Jonathan Swift to investigate Horizon and the convictions based on evidence from the system.

Swift suggested that the Post Office may have “bullied” sub-postmasters into pleading guilty to false accounting by charging them with the more serious offence of fraud, despite there being insufficient evidence of fraud. Swift said the matter was of “real importance to the reputation” of the Post Office and a “stain on the character of the company”.

He also found that Horizon “sometimes suffered from bugs that led to losses in some industries” and warned that there may have been miscarriages of justice.

Swift’s review included a series of recommendations to investigate Horizon further. However, Parker was advised by Jane MacLeod, the Post Office’s general counsel, that he could not share the review with the board of directors, which he chaired, because the document was legally confidential.

As a result, the research was also not made available as evidence during the 2018/19 High Court trial which showed that bugs in Horizon were responsible for the fictitious accounting losses in the system.

In October 2020, Parker was criticised in a letter by Sarah Munby, then Permanent Secretary at the Department for Business, Energy and Industrial Strategy (the government department that managed the relationship with the Post Office and was responsible for his appointment as chair), over his decision to keep the Swift inquiry outside the board.

“We believe it was a mistake not to ensure that the entire board had the opportunity to see and discuss the details of the findings and agree what the next steps should be. In hindsight, the board should have seen this information and we are disappointed that it did not,” Munby wrote.

“We believe that, as a general rule, it is difficult to conceive of circumstances in which issues of legal privilege or confidentiality would prevent the sharing of relevant information with a company’s board of directors.”

When asked by investigating attorney Jason Beer, QC, Parker said: “It was always intended that the Swift investigation would be legally privileged,” adding that he had been briefed on this by “general counsel,” meaning MacLeod.

Parker said he expected the document to be shared more widely once the recommendations were implemented.

“It is one of my regrets that I was given that advice and followed it,” he told the inquiry.

“My view at the time – and perhaps this was a bit naive – was that the recommendations would come quite quickly and that we would be able to talk about the report as completed, but unfortunately that didn’t happen… Could we have shared it? I wish we had.”

He said MacLeod told him that only four copies of the report would be made and that they would all be kept by her legal department.

In order to ensure legal confidentiality, MacLeod took responsibility for implementing the recommendations of the Swift inquiry. However, before this could be completed, the Justice for Subpostmasters Alliance campaign launched legal proceedings against the Post Office.

Parker was subsequently advised in 2016 by MacLeod and the Post Office’s external legal advisers that work on the Swift review should be halted because the upcoming litigation would address the issues raised by the review – and that legal privilege over the review should be maintained.

The Swift inquiry remained secret until 2022, when freedom campaigner Eleanor Shaikh called for it to be declassified. MacLeod, now living in Australia, has refused to appear as a witness before the inquiry.

The Post Office scandal was first exposed by Computer Weekly in 2009, which revealed the stories of seven subpostmasters – including Alan Bates – and the problems they encountered with accounting software. It is one of the biggest miscarriages of justice in British history (See below for a timeline of Computer Weekly articles on the scandal, since 2009).

• Also read: What you need to know about the Horizon scandal •

• See also: ITV’s documentary – Mr. Bates vs. the Post Office: The Real Story