Tony Blair is facing damning criticism of his role in the Iraq war from the official inquiry into the 2003 invasion, it was claimed last night.

The Chilcot inquiry is expected to round on the former prime minister when it produces its final report after more than a year of exhaustive hearings and deliberations, according to a report in The Mail on Sunday.

The newspaper claimed that Mr Blair, who was instrumental in the drive to war alongside the then-US President George Bush, will reportedly be held to account in four key areas:

* Bogus claims made about the weapons of mass destruction allegedly held by the Iraqi leader, Saddam Hussein;

* The failure to tell the British public about his "secret pledge" with President Bush to go to war;

* The operation of a "sofa government" style, which kept his Cabinet in the dark over the planning for an invasion of Iraq;

* The failure to foresee the chaos that gripped Iraq following the invasion, and to lay realistic plans to deal with it. Officials are currently writing the report and all witnesses will be given the chance to respond to any inaccuracies.

Mr Blair led the country to war eight years ago amid nationwide protests. His successor, Gordon Brown, set up the Chilcot inquiry after criticism of previous probes.

Mr Blair mounted a vigorous defence of the 2003 invasion of Iraq when he appeared before the inquiry for the first time, insisting that he had no regrets over removing Saddam and would do the same again.

But critics of the war and families of the 179 British troops who died in the conflict condemned his evidence, saying he evaded the panel's questions and refused to admit his mistakes. He gave evidence a second time and was jeered as he said he "deeply and profoundly" regretted the loss of life in the Iraq war.

In his memoirs, A Journey, he said he was angry at the way he was asked whether he had any regrets about going to war. He wrote that the Chilcot inquiry was supposed to be about learning lessons but had "inevitably turned into a trial of judgment and even good faith".

A spokeswoman for the Chilcot inquiry said: "We will not provide a running commentary on the inquiry." A spokesman for Mr Blair was made aware of the claims last night butdid respond by the time of going to pressed.

The Mail on Sunday said that "well-placed sources say the reputations of Mr Blair and key allies will suffer major damage when the report by Sir John Chilcot's Iraq war inquiry is published this autumn. Mr Blair, the former foreign secretary, Jack Straw, and spin-doctor Alastair Campbell are all expected to be criticised."