According to reports the much-delayed findings of the Iraq Inquiry into the background to the conflict conflict that began in 2003 has been held up by the process of Maxwellisation - giving individuals criticised in the report a chance to respond.
A source at the inquiry chaired by former top mandarin Sir John Chilcot told BBC Newsnight that the process had become a “nightmare”.
Former Prime Minister Tony Blair, who took the UK into the war, has already denied that he has sought to delay the publication which MPs and campaign groups had demanded ahead of the election.
The report is expected to severely criticise individuals on taking the UK into war and make conclusions on the conduct of the conflict.
Newsnight’s defence and diplomatic editor Mark Urban quoted a source close to the investigation as saying “nobody thinks it will come out this year”.
The inquiry’s chairman Sir John Chilcot has been forced to defend delays after he said in January it would not be finished before May’s general election.
Prime Minister David Cameron has been among those expressing frustration that the report has yet to be finalised, more than five years after the inquiry, which took evidence from its last witness in 2011, was launched.
Lib Dem Deputy Prime Minister Nick Clegg said he was “dismayed beyond belief” at the reported delay.
He said: “I’m just dismayed beyond belief that we are having to wait so long - and now, it is being reported, even longer than I had feared - to finally find out the truth of what happened in the run-up to that fateful - and what I have always considered, personally, to be illegal - invasion of Iraq.”
SNP Westminster leader and foreign affairs spokesman Angus Robertson said: “For the Chilcot report to be subject to yet more delays is completely unacceptable, and will be greeted with dismay by the hundreds of thousands of people whose lives were affected by the Iraq war.
“People deserve full disclosure about how the Labour government at Westminster operated in the lead up to this disastrous war.
“There is clear cross-party support both the Scottish Parliament and Westminster for early publication of this vital report – subjecting it to yet more delay is quite frankly an affront to democracy and the process of Parliamentary scrutiny.”
He added: “The Iraq war was a foreign policy disaster whose ramifications are still being felt today. Answers are long overdue, and the continued delays to the publication of this report cannot are a democratic outrage.”
Ukip deputy chairwoman Suzanne Evans said the “endless delays” were “completely unjustifiable”.
Speaking at a small business policy briefing in central London, she added: “That’s nothing new, is it?
“We have been calling for it for some time.
“We have had a petition online actually, asking for it to be published. What are they so frightened of?
“It seems to have been beset by endless delays, which seem to me to be completely unjustifiable.
“I think our response is exactly the same as it was a couple of months ago - that it’s about time it was out.
“We have always felt they were going to kick it into the long grass until after the election.
“Once again they are showing that’s exactly what they intend to do.”
The BBC quoted the source as saying “once they had failed to meet the pre-election deadline, they gave up trying to speed things up”.
Mr Urban said some of those criticised in the report had been given drafts running to “hundreds of pages”, while others “engaged in lively correspondence with the inquiry team” in order to defend themselves.
He said: “Those I have spoken to speak of poorly-drafted letters from the inquiry that have required clarifications and given those disputing the inquiry’s findings room to deploy their own arguments. Some have engaged lawyers to assist with their defence.”
In February, Sir John told MPs: “My committee and I want, and intend, to deliver our report to the Prime Minister as soon as we possibly can. But as I said to the Prime Minister ... I see no realistic prospect of doing so before the General Election.
“It is our duty to deliver a report which gives the Government, Parliament, the public, and particularly all those who have been deeply affected by events in Iraq, the answers they deserve.”