Nick Read told staff he wants to give his "entire attention" to hearings in September that will examine current practice at the Post Office.
Post Office chief executive Nick Read is stepping back from the role temporarily to prepare for the next stage of the Horizon scandal inquiry.
Mr Read, who succeeded the heavily-criticised Paula Vennells after she stepped down in 2019, told staff in a note that he wanted to give his "entire attention" to the stage of the hearings in September that will examine current practice at the Post Office.
His deputy, Owen Woodley, would run the day-to-day business from Monday 15 July until the end of August, it revealed.
Mr Read's note, first reported by the Post Office scandal-focused journalist Nick Wallis, said of his decision: "It is vitally important that we demonstrate the changes we have made and give confidence to the inquiry and the country at large that 'nothing like this could happen again'."
Between 1999 and 2015, more than 700 sub-postmasters were prosecuted on charges such as theft and false accounting after faulty accounting software provided by Fujitsu made it seem like money was missing from their branches.
While the sub-postmasters' convictions have been overturned, many are still struggling to secure full compensation under processes aimed at speeding up final redress.
The inquiry has heard repeated denials of a cover-up from key figures including executives and lawyers.
Among the witnesses was Mr Read's predecessor, who handed back her CBE - awarded in 2019 for "services to the Post Office and charity" - amid public anger over the scandal following the screening of the ITV drama Mr Bates vs the Post Office.
Ms Vennells told the inquiry she had been too trusting of individuals involved in handling growing questions over past prosecutions, admitting it amounted to a "lost decade" in identifying the miscarriages of justice.
Mr Read's tenure has been dominated by the fallout amid efforts to restore confidence in the Post Office.