The former UK head of Fujitsu during part of the Post Office scandal has resigned from his role at the Cabinet Office.
Michael Keegan, who is married to Education Secretary Gillian Keegan, is understood to have resigned voluntarily from his part-time role.
He has been approached for comment.
Mr Keegan was Fujitsu's UK chief executive between May 2014 and June 2015. The tech company was behind the faulty Horizon bookkeeping software.
The Cabinet Office declined to comment on his resignation as a Crown Representative, managing the relationship between BAE Systems and the government.
The Horizon system generated false evidence of cash shortfalls at sub-post offices, leading to one of the biggest miscarriages of justice the UK has ever seen.
Between 1999 and 2015, the Post Office prosecuted 700 sub-postmasters and sub-postmistresses - an average of one a week - based on faulty information from the Horizon system.
Some went to prison for false accounting and theft, while others were financially ruined.
Many maintained their innocence and said they had repeatedly reported problems with the software, but Post Office bosses kept insisting their systems were robust.
During Mr Keegan's time as CEO, flaws in the Horizon computer system began coming to light. In January 2015, the Commons business committee launched in inquiry into Horizon and the Post Office's scheme, hearing evidence from then Post Office chief executive Paula Vennells that the system was robust.
His position as CEO had ended before the legal case by the sub-postmasters against the Post Office began in 2016.
He moved to head up of Fujitsu's Technology Product Business for an area, including Europe and Middle East, two months before a BBC Panorama expose of the scandal engulfing the Post Office.