Caroline Lucas called Tony Blair a "war criminal" at a demonstration held in London today as the Chilcot report into the Iraq War was finally released.
Protesters congregated outside the Queen Elizabeth II Conference Centre on Wednesday where Sir John Chilcot was delivering the findings of his inquiry.
The long-awaited official report into Britain's controversial invasion of Iraq was finally published amid calls for former British Prime Minister Blair to be held to account for taking the country to war.
Lucas addressed the crowd, calling the war "illegal and immoral".
The Green Party MP said she had been looking at the report since 8am today. She told the protesters "it confirms just about all of your worst fears".
Lucas said: "It confirms what we know, that Tony Blair lied when he took this country to war on a false prospectus.
"It lays bare for us to see that he made commitments to George Bush six months before he stood up in parliament saying Saddam Hussein could still avoid war.
"That was not true and we will hold him to account."
Lucas continued: "He lied by setting standards for the weapons inspectors which he knew would be impossible for those weapons inspectors to meet.
"He lied by pulling those weapons inspectors out of Iraq before he knew they had been able to finish the job that had been set for them.
"He lied when he said that the threat from Weapons of Mass Destruction was growing when he knew there was no evidence to make that case.
"And so friends we have been right to be holding Blair to account. We are right to say that he should be held to account at the highest level possible in this country.
"Friends, I believe that Tony Blair is a war criminal."
The MP for Brighton said that Blair put the lives of British soldiers at risk in a "cavalier" way.
Supporters of Stop the War read out the names of Iraqi and British dead to the gathered crowds.
Pictures outside the QEII Centre show a heavy police presence at the demonstration.
Protestors held up placards, with slogans such as "Bliar", "out damned spot" and "put Blair on trial".
On the Facebook page set up ahead of today's protest, the group wrote: "After a seven year wait the Chilcot Report is finally going to be published on June 6th.
"Despite its astounding length (2.3 million words) it is highly likely that it will fall short of an outright condemnation of the Iraq war and fail to apportion blame to those who were truly responsible for the catastrophe."