People have "probably" died as a result of the ongoing delays in publishing the Iraq Inquiry report because politicians have not learned from the mistakes of the war, MPs have been told.
Senior Conservative David Davis said recent decisions about intervention in Libya, Syria and Iraq were made without proper knowledge of the controversial 2003 choice to go to war.
As a result bad decisions have been made which have probably cost lives, the former foreign minister said.
The long-awaited Chilcot report into Iraq is due to be handed to Government officials on Monday, when national security checks will begin.
Mr Davis and other MPs are calling for it to be published in the first week of May.
Opening a backbench debate on the inquiry, he told the Commons: "There are lessons to be learned from the Iraq War about our foreign policy, about our political decisions to go to war and about our military operations.
"The longer we leave it the less useful these lessons will be and the more likely it is that we will make the same mistakes.
"A decision such as those that were made in Libya, Syria and Iraq are made without the knowledge or facts, mistakes are made, and sometimes people die as a result.
"It's not hyperbole to say delay to the Iraq Inquiry could cost lives because bad decisions could be made - I would go further, I'd say it probably did cost lives because bad decisions were made."
Mr Davis dismissed as "outrageous" suggestions the report may now be delayed until after the June 23 EU referendum, given that Prime Minister David Cameron has said security vetting should only take two weeks.
He stressed that the Saville Inquiry into Bloody Sunday, which took years to complete, was published after two weeks of vetting.
Mr Davis went on: "So I cannot believe that the clearance will take any longer than this, given as we already know every single piece of this report has already been negotiated with Whitehall, presumably on the basis of security considerations."
He added: "The public ought to expect publication of the report in the first week of May, that should be the reasonable conclusion, but this is not the case.
"There are now reports that the publication of the report is going to be postponed until after the EU referendum at the end of June.
"This is frankly outrageous."
The inquiry was set up in 2009 by then-prime minister Gordon Brown and its final round of hearings took place in 2011.
Downing Street appeared to dismiss suggestions that the report might have to be held back until after the June 23 referendum on Britain's EU membership.
Asked whether there was any reason why the report could not be published before the vote, the Prime Minister's official spokeswoman told a regular Westminster media briefing: "The PM's view is that he wants to see this report published as soon as possible. The timing is in the hands of Sir John Chilcot."
The spokeswoman said that Government experts will be sent to Sir John's office to carry out national security checks on the report before it is proof-read and prepared for publication.
"We will be getting on with the national security checking that is a standard part of this kind of report as soon as possible," she added.
Sir Gerald Howarth, a shadow defence minister when he voted in favour of the war, partly over fears that Saddam Hussein could launch chemical weapons at 45 minutes' notice, said politicians also deserve to know the truth behind the claims presented to them.
The Tory MP said: "It's not just the bereaved, it's those of us who were in the House at the time, for all of us bore a responsibility for the decisions we made and whether to vote for this war or not.
"But those of us who were on the front bench had a special responsibility but we had no more information than what we read in the newspapers."
Labour's Paul Flynn said it was vital that politicians understood the "mindset" that led to the decision to go to war in the face of subsequent conflicts.
He said: "It is absolutely crucial we understand that mindset that drove us into war - and that mindset is one that we heard recently in other debates here, with going into Libya, or into Syria, and is this myth, that affects English MPs rather than Scottish or Welsh or Irish MPs, and it's the idea that the UK, our country, must punch above its weight militarily.
"That always means spending beyond our interests and dying beyond our responsibilities."
He added: "There's no excuse of delaying this any further, not for a single day. The loved ones deserve closure.
"They've waited far too long. It's only in the political interests of those who are responsible, the guilty ones, to continue."
Intervening, Labour's Graham Allen said admitting the mistake of going to war was necessary to "purge" the Labour Party.
He said: "The publication will be part of what is necessary to purge our own party of the fault line that occurred around the time of the Iraq War and continues to this day.
"And also besmirches the reputation of an otherwise very fine prime minister, who until we admit the mistake of going to Iraq, of opening this Pandora's box, will forever be known as the person who took us to war on the coat-tails of George W Bush, against so many of his colleagues who were in the House at the time, and a mistake needs to be corrected.
"It will be good for all of us on these benches if nowhere else."
The SNP's Angus Brendan MacNeil, who said he was against the Iraq War, urged the swift publication of the report.
"We expect the military do their jobs when we commit them to war ... we ourselves should be prepared to do our job," he said.
He added: "The UK risks becoming an international laughing stock by this infinite and eternal delay that's tied with this report."