Former foreign secretary Jack Straw is being lined up for a seat in the House of Lords after he steps down as an MP in May.

The former Foreign Secretary is understood to be open to accepting a peerage and could even take up his place on the red benches before his role in taking Britain to war against Iraq is laid bare in the long-delayed Chilcot report.

A senior Labour source told MailOnline the Blackburn MP is 'on his way down the corridor to the other place' after he leaves the Commons.

Jack Straw was instrumental in taking Britain to war in Iraq in 2003, as Tony Blair's long-serving foreign secretary

It comes amid growing anger at the four-year delay of the Chilcot Inquiry's report, which is now facing a race against time to be published before 2016.

The revelation that Mr Straw could be handed a peerage before the Chilcot report is likely to anger anti-war campaigners who attacked his support for the 2003 invasion during a fiery Commons debate last week.

Mr Straw – who was foreign secretary from 2001 to 2006 – is expected to be rebuked by Sir John Chilcot when he finally published his report after the election.

Well-placed sources have revealed 'approximately 30' people have been sent letters by Sir John warning them that they will be criticised in his report into the invasion, including Mr Straw.

Downing Street insiders expect the report to be a 'devastating' indictment of the Blair Government and large sections of the Whitehall establishment.

Mr Straw, who gave evidence to the Chilcot inquiry three times, has insisted suggestions the report it being delayed by witnesses were 'wholly without foundation'.

He told MPs it was in his interest for the report to be published as soon as possible.

Mr Straw also suggested that criticism of the delays to the Chilcot inquiry could lead to the panel producing conclusions that were 'more starkly drawn than the evidence'.

During his evidence sessions he expressed his 'deep regret' about the war and said he supported the decision to attack Iraq 'very reluctantly'.

He acknowledged he could have forced Blair to think again had he objected, but rejected advice from Foreign Office legal experts that to attack UN support 'would amount to a crime of aggression'.

Sir John Chilcot was last week summoned before Parliament to explain why his report had been delayed again

Sir John was last week summoned before Parliament to explain why his report had been delayed again.

He was asked by MPs last week to say how many people had been told they will be criticised in the report, but he refused point-blank. 'At the risk of being obdurate, I mustn't. If I start to give numbers people can work out who might be involved.'

He told MPs he would deliver his report 'as soon as we possibly can' but renewed his assertion that he saw 'no realistic prospect' of it being finished before May's general election.

He said he had accepted a summons to explain the hold-ups because he recognised the 'exceptionally high level of parliamentary and public interest in our progress'.

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.