Caroline Lucas, the Green MP for Brighton Pavilion, has joined a cross-party group of MPs in preparing a motion aimed at holding Tony Blair to account over the Iraq war.
The move – which would bar the former Prime Minister from holding any public office – follows a two-day debate on the Chilcot report into the war.
Caroline Lucas’s office said: “It is planned to lay a motion of censure or contempt of Parliament which will argue that the Iraq inquiry provides a sufficiency of evidence to bring the former Prime Minister to book.
“Among the supporters of the campaign are long-term opponents of the Iraq war such as Alex Salmond MP and Kate Hoey MP.
“However, the group also includes respected Tory backbenchers such as Sir Roger Gale and David Davies.
“The group has been meeting in private for some weeks awaiting the Chilcot publication and have taken legal advice from a number of international lawyers.
“The group has also been advised by the former Plaid Cymru MP, Adam Price, who led a campaign to impeach the then sitting Prime Minister more than a decade ago.
“However, Chilcot went much further than many expected in presenting a comprehensive case against the Blair government.
“As a result the MPs believe that the case for some form of parliamentary action is now overwhelming.”
Caroline Lucas, a longstanding opponent of the Iraq war, said: “The Chilcot report is a damning indictment of Blair’s record. It showed that the former Prime Minster actively deceived Parliament and led this country into a disastrous and bloody war under false pretenses.
“I’m joining with fellow MPs to hold Blair to account by tabling a contempt motion which could see him barred from public office and have his privy counsellorship stripped from him.”
A spokeswoman for the group said: “This initiative does not interfere in any way with legal action either by the authorities in terms of criminal law or by the service families in the civil courts.
“However, there is a specific parliamentary matter in holding the former prime minister to account given the revelations in Chilcot.
“Most damning of all is the detailing of what Blair was telling Bush in private memos while he was telling Parliament and people something entirely different in public statements.
“If we are to prevent such a catastrophe happening again it is essential that parliamentarians learn to hold the executive to critical examination in a way that Parliament failed to do in 2003.
“Holding Blair to account will be an essential part of that process of parliamentary accountability.
“The case has been made by Chilcot and any Parliament worth its salt is duty bound to take action.”