Post Office boss Nick Read joined long after the events which eventually sparked the Horizon scandal, but his tenure has been dominated by the crisis.
Mr Read, 59, said on Wednesday that it was a “great privilege” to have worked as chief executive, as the company announced that he would leave in March 2025.
A former army officer, Mr Read was boss of Nisa Retail and of now-defunct energy supplier Extra Energy before joining the Post Office in 2019.
It was not until September 2020 that a public inquiry into the scandal was opened, which eventually led to the 2024 ITV drama, Mr Bates Vs The Post Office.
The show thrust the matter to the forefront of public life through the story of lead campaigner and former subpostmaster Sir Alan Bates.
In the intervening years the inquiry has heard evidence of how more than 900 subpostmasters were prosecuted for stealing, based on incorrect information from the Horizon IT system.
That included accusations from the former HR director of the Post Office that he was “obsessed with his pay”, and that he repeatedly made threats to resign over the issue.
Jane Davies, who held the role from November 2022 to July 2023, wrote to MPs in April saying that at one point Mr Read was offered a 5% pay rise but appeared to find it “insulting”.
She said he had even embarked upon a “deliberate campaign to defame and ostracise her”, after she was brought into the company “with a mandate to tackle deep-seated cultural problems within the organisation and prioritise redress for the victims of the Horizon scandal”.
Mr Read was also the subject of an investigation by an independent barrister, who looked into allegations against the chief executive including accusations of “bullying” by former chairman Henry Staunton.
But the Post Office later said the review “exonerated” him of misconduct claims, and that he had the full backing of the board to continue to lead the business.
That also came after the Business and Trade Select Committee of MPs expressed a lack of confidence in his leadership, accusing him of giving misleading evidence.
He said on Wednesday that there “remains much to be done for this great UK institution but the journey to reset the relationship with postmasters is well under way”.
Sir Alan, on the other hand, gave a different assessment.
Speaking to the PA news agency, he said of Mr Read: “Well, he really hasn’t achieved anything, has he?”
He added: “He certainly hasn’t done anything for the victims in all of this.”