The Chilcot Inquiry will be held in contempt if it does a ?whitewash? by omitting to disclose details of a ?foreign policy disgrace of epic proportions?, Sir Ken Macdonald, QC, Director of Public Prosecutions until last year, says in an article for The Times.

In perhaps the most serious charges levelled by a former public servant against an ex-Prime Minister, Sir Ken says Mr Blair engaged in an ?alarming subterfuge? with George Bush, and then misled and cajoled the British people into a war they did not want.

Mr Blair?s fundamental flaw was his sycophancy towards those in power, he says. ?Perhaps this seems odd in a man who drank so much of that mind-altering brew at home. But Washington turned his head and he couldn?t resist the stage or the glamour that it gave him.?

Mr Blair?s mantra that he did what he thought was right was a ?narcissist?s defence? because self-belief was no answer to misjudgment and no answer to death.

In his most savage passage, Sir Ken, who was appointed in 2003 under the Blair government and practises at the same London Chambers as the former Prime Minister?s wife, writes that the heart-rending sacrifices made by British forces would become the stuff of poetry and song in future years. But none of that would sprinkle any starlight on Mr Blair. ?On the contrary it is entirely the work of warriors cast carelessly into death?s way by a Prime Minister lost in self-aggrandisement and a governing class too closed to speak truth to power.?

Sir Ken?s intervention comes after Mr Blair?s declaration in a BBC interview that he would have favoured removing Saddam Hussein regardless of whether he had possessed weapons of mass destruction.

The inquiry yesterday insisted that Mr Blair would give evidence in public, after reports that he might not. A spokesman for the inquiry said: ?Mr Blair will be appearing very much in public and will be questioned in detail on a wide range of issues.?

Sir Ken suggests that the inquiry?s performance so far has been generally unchallenging and he goes close to warning of an Establishment cover-up. ?In British public life loyalty and service to power can sometimes count for more to insiders than any tricky questions of wider reputation. Disloyalty, on the other hand, means a terrible casting out.?

It was the privately arranged nature of British Establishment power that had brought politics so low. ?If Chilcot fails to reveal truth without fear in this Middle Eastern story of violence and destruction, the inquiry will be held in deserved and withering contempt.?

Mr Blair secured support from the Commons for the Iraq war largely on the ground that it was needed to remove weapons of mass destruction.

Bob Ainsworth, Defence Secretary, who was deputy chief whip at the time of the vote in March 2003, said yesterday: ?I supported the war in Iraq based on the arguments that were put at the time and a big part was ? and I firmly believed that they existed ? the existence of WMD.? Asked if he was surprised by Mr Blair?s remarks, Mr Ainsworth replied: ?A little bit.?

Mr Blair refused to comment.