Any failure to publish in full the discussions held between Tony Blair and George Bush in the run up to the Iraq War will leave the decision to launch the 2003 invasion clouded in suspicion, Sir John Major has warned.
Years of negotiations over the publication of the "vital" material, which includes 25 notes from Blair to Bush and more than 130 records of conversations between the former prime minister and then-US president, is understood to have been behind the delay in publication of the long-awaited Chilcot Inquiry report into the invasion.
On Thursday it was announced that the inquiry would be allowed to release details of the talks. However the extracts will be edited and only the "gist" of the high-level discussions will be made public.
Major told BBC Radio 4's Today programme on Friday morning that unless the conversations were released in full, public distrust over Blair's handing of the war would only "fester".
"I think it is a pity the papers are going to be withheld for several reasons. Firstly, they will leave suspicions unresolved and those suspicions will fester and maybe worsen," he said.
"Secondly, in many ways I think withholding them is going to be very embarrassing for Tony Blair, not least of course because he brought the Freedom of Information Act into law when he was in government."
Under the rules only the previous Labour government could approach the Cabinet Office, which handled the negotiations, for the papers to be released. "Maybe, in their own interests, they should think about that because otherwise, as I say, this will fester and I don't think anybody wishes to see that," he said.
The Chilcot Inquiry was set up in 2009 by Gordon Borwn in an attempt to draw a line under the controversy over how Britain was led to war, but has been beset by delays.
Earlier this month Conservative defence minister Andrew Murrison, who served in the conflict as a Royal Navy reservist, predicted that the inquiry's report would not be "very kind" to Blair. And he told The Huffington Post that the report needed to be published as soon as possible.
"These things have a tradition of taking a while. But this really is getting beyond any sense of reasonableness and it is simply not clear to me why we haven’t the inquiry report in the public," he said.
"I think parliament was let down by an individual that they had every right to expect would with deal with them fairly. At the end of the day that is for Tony Blair and his conscience. I'm hoping Inquiry will shed some light."