The boss of the Post Office has apologised for receiving bonus payments related to an inquiry into a long-running miscarriage of justice, and said hundreds of postmasters had found it “too traumatising” to come forward to challenge their convictions. The company is being investigated by the government after the Post Office admitted it had wrongly paid thousands of pounds of bonuses to top executives simply for cooperating with an inquiry into the Post Office’s faulty Horizon computer system. The IT system resulted in 700 postal workers being wrongly convicted of theft and false accounting between 2000 and 2014. The scandal led to some operators being sent to prison, and has been blamed for four suicides. Nick Read, the chief executive of the Post Office, and other senior staff received bonuses partly related to supporting the inquiry, led by the retired high court judge Sir Wyn Williams. Williams said he had not approved the bonus payment even though the Post Office stated in an annual report that it had received confirmation from him. Read, a former Thomas Cook and Vodafone executive who took over in 2019, said he had returned the portion of his £455,000 bonus for 2021-22 that was related to the inquiry. Overall, 30 out of 34 senior Post Office staff have done so. Questioned by MPs on the business and trade committee, Read apologised “unreservedly” for the error. Both he and the Post Office chair, Henry Staunton, who was appointed last September, said it was important to ensure such mistakes would not happen again. “Let me apologise for the error and the mistake that has been made in our incentive scheme,” Read told MPs, reiterating an apology made when the payments emerged last month. “When the scheme was established it was part of the transformation of the Post Office. Clearly the independent inquiry became a statutory inquiry half way through the scheme term, and the mistake was that we didn’t go back and revisit that particular incentive. “That was an error and I apologise unreservedly for that, and that’s certainly something that we should have identified.” He insisted that the error was not “dishonest” or “malicious”. Staunton said he had described the mistake as “baffling” in a letter to the Department for Business and Trade. Separately, Read said that just 86 of the 700 wrongful convictions of postmasters had been overturned or appealed following what he described as “a horrific miscarriage of justice”. He said that the number would have been higher but admitted that many victims were not willing to engage with the Post Office. “I’m deeply troubled that people aren’t coming forward,” Read said. “Having met with a number of them, I can understand why. It’s too traumatising. “I’ve come across individuals who won’t even open mail from the Post Office, who simply won’t enter into the spirit of the remediation we’re trying to do, which is why we’ve been using external agencies to see if there’s a different way to engage.” He said he was going to Northern Ireland on Thursday to meet five postmasters who had been through this process to try to understand what can be done to encourage more to come forward. The government said last year it would pay former Post Office operators up to £1bn in compensation, after the company said it could not afford the bill. The Post Office boss said nearly all of the postmasters who had applied for compensation – 2,402 individuals – had received a compensation offer; 82% had accepted these offers and 71% had received payouts. Read reiterated there was no cap on compensation payments, amid criticism that they were far too low. The government investigation will run in parallel to an internal Post Office investigation by non-executive director Amanda Burton, who has taken over the company’s remuneration committee. Speaking in front of the business and trade committee, her predecessor, Lisa Harrington – who signed off on the bonuses, also reiterated her apology and said she was “disappointed in myself”.