Next year, Post Office CEO Nick Read, who is currently under fire, will step away.

Read had previously temporarily resigned from his position in July to devote his "entire attention" to getting ready for his appearance. Read is scheduled to testify in October before the state-owned body's investigation into the Horizon IT disaster.

On a day-to-day basis, Neil Brocklehurst will take over as interim CEO. Read's resignation was initially reported by Sky News.

The Post Office Horizon IT scandal led to hundreds of post office operatives being wrongly prosecuted for theft and false accounting owing to financial shortfalls in their branch accounts. It has since emerged these discrepancies were caused by IT bugs in the Post Office Horizon computer system. The former prime minister Rishi Sunak described it as “one of the greatest miscarriages of justice in our nation’s history”.

The public inquiry, which is scrutinising failings at the Post Office that led to the scandal, is due to start its seventh phase of the hearings and will examine current practices. Read is expected to testify for three days starting on 9 October.

The Post Office said it would now begin the process of appointing a new chief executive to replace Read when he steps down on 15 March 2025.

Nigel Railton, the interim chair, said: “It has been a challenging period for the Post Office and its postmasters, and Nick has been instrumental in navigating the business through this while beginning the important process of cultural change.”

Read said: “It has been a great privilege to work with colleagues and postmasters during the past five years in what has been an extraordinarily challenging time.”

He took over as chief executive in September 2019 with a remit to modernise the institution, succeeding Paula Vennells. She forfeited her CBE in February amid public anger over her handling of the Horizon crisis.

Read led the settlement of the high court lawsuit in late 2019 brought against the Post Office by the campaigner Sir Alan Bates and 554 post office operatives. The case exposed failings in the Horizon IT system and helped pave the way for hundreds of operatives to have their wrongful convictions overturned.

Read’s tenure has been dominated by the scandal and mired by controversy. Last year he returned a bonus payment linked to the public inquiry and apologise for “procedural and governance mistakes” by the company.

He promised to overhaul the Post Office and “right the wrongs of the past”, but became embroiled in a reputational crisis of his own when, in March, the business and trade committee of MPs expressed a lack of confidence in his leadership, accusing him of giving misleading evidence.

In April, Read was “exonerated of all misconduct allegations” after an investigation into alleged bullying.