The scandal, which is one of the UK’s biggest miscarriages of justice, saw dozens of subpostmasters wrongly convicted and in some cases jailed for accounting problems with missing money in their branches that were actually the result of a faulty Post Office IT computer system called Horizon.
Sir Ed was Postal Affairs Minister in the Coalition Government for 19 months and was contacted by subpostmasters about the problem in 2010.
In May this year, shortly after dozens of convictions of subpostmasters for fraud and theft were overturned at the Court of Appeal, The Times reported that Sir Ed had been written to by Alan Bates, head of the Justice For Subpostmasters Alliance in May 2010, warning him that “many people have been sent to prison, lost businesses and homes and faced financial ruin by an organisation that will stop at nothing to keep the true facts behind its failing IT system from being exposed”.
Sir Ed wrote back to him at the time to say the Post Office was continuing to express its "full confidence in the integrity and robustness of the Horizon system".
When asked by The Yorkshire Post whether he regretted not doing more about the issue, Sir Ed said: “This issue began I think about in 1999.
“When I came to office it had been kicked around by ministers for over a decade.
“I guess other ministers, both Labour and Conservative, relied on the advice of the Post Office and of the senior managers of the Post Office.
“We ask real questions and I wish maybe we'd ask more.
“The Post Office clearly should be more transparent with ministers. There are definitely questions that they should answer - this is why I've supported a public inquiry into the scandal.
“I think a public inquiry is the right thing so we do all we can to ensure injustices like this don't happen again.
“With hindsight I wish I could have done more during my 19 months as Post Office Minister, I'm sure all the other Post Office ministers over this 20 year period wish they'd have done more.”
Over 50 subpostmasters have had convictions overturned, with hundreds more hoping for similar decisions.
Between 1999 and 2015, they were sacked or prosecuted after money appeared to vanish from accounts at their branches.
The problems were caused by the flawed Horizon computer system used by the Post Office but the organisation pursued prosecutions of subpostmasters rather than admit to problems with the IT system.
Some subpostmasters - including several in Yorkshire - were imprisoned after being convicted of stealing money.
A statutory inquiry into the scandal led by retired High Court judge Sir Wyn Williams has been ordered, with its work at a preliminary stage.
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