Former Prime Minister Tony Blair could be faced with charges for war crimes committed during the Iraq war.
A cross-party group is considering using an ancient Parliamentary mechanism to bring him to trial in Westminster.
They say Mr Blair should be forced to answer claims he duped the Commons over the war, which cost the lives of 179 British troops.
The MPs believe they can argue that the ex-Labour leader should be impeached over allegations he breached his constitutional duties as Premier.
The power has not been used since 1806 when Lord Melville, a Tory minister, was charged with misappropriating official funds by the Commons. He was acquitted.
Mr Blair, who made claims about Saddam Hussein’s weapons of mass destruction that were contradicted by his own intelligence assessments, is expected to be heavily criticised in the Chilcot Inquiry report.
One Westminster source said: ‘Impeachment is on our minds but we will need to digest the report. There is definitely a feeling that Blair must be properly held to account for his actions in the run-up to what was a disastrous war.’
One MP can trigger the process by proposing a motion. He or she would need to present evidence to support their case and this would form the basis of a document called the Article of Impeachment, drawn up by a committee of MPs.
If the impeachment attempt is approved by MPs, the defendant is delivered to Black Rod ahead of a trial. A simple majority is required to convict, at which point a sentence can be passed, which could, in theory, involve Mr Blair being sent to prison.