Giving his own evidence, Mr Cook was asked by Sam Stein KC, on behalf of a number of subpostmasters: “In your statement, you say this: ‘To the best of my knowledge the risk and compliance committee was not given any information or reporting, nor did I have any oversight of the prosecution of subpostmasters.

“‘As a result I did not take any steps … to ensure the Post Office was acting in compliance with its legal obligations. In relation to those prosecutions and civil proceedings against subpostmasters, I was not aware they were taking place.’

“It’s just a straight-out lie, isn’t it Mr Cook?”

He replied: “The point I was trying to make was about the initiation of prosecutions — I have repeatedly acknowledged that there were cases under investigation and that I was aware there were cases under investigation.”

Mr Cook added his email about “subbies with their hands in the till” was “unacceptable” and one he will “regret for the rest of my life” and that it was his regret that he failed to properly understand minutes of a risk and compliance committee meeting from September 29 2005 which said the Post Office had a “principle of undertaking prosecutions.”