Tony Blair could be put on trial for his role in taking Britain to war in Iraq.
MPs are examining whether the former Prime Minister can be impeached and forced to account for his actions in front of MPs and peers.
Under impeachment rules "holders of public office, for high treason or other crimes and misdemeanours" can be put on trial in Parliament.
Excerpts from Tony Blair's address
The decision to go to war in Iraq and remove Saddam Hussein from power in a coalition of over 40 countries led by the USA, was the hardest, most momentous, most agonising decision I took in 10 years as British Prime Minister.
For that reason, today I accept full responsibility, without exception and without excuse. I recognise the division felt by many in our country over the war and in particular I feel deeply and sincerely - in a way that no words can properly convey - the grief and suffering of those who lost ones they loved in Iraq, whether the members of our armed forces, the armed forces of other nations, or Iraqis.
The intelligent assessments made at the time of going to war turned out to be wrong. The aftermath turned out to be more hostile, protracted and bloody than ever we imagined. The coalition planned for one set of ground facts and encountered another, and a nation whose people we wanted to set free and secure from the evil of Saddam, became instead victims to secular terrorism.
For all of this, I express more sorrow, regret and apology than you may ever know or can believe.
Tony Blair isn't the only one who should acknowledge the mistake and apologise for supporting President Bush by sending troops to Iraq, our Prime Minister John Howard and most of the free world went with him.
And by the time we woke up and discovered that thousands of innocent civilians died for no reason and the war was started on a lie, it was too late.
This week, John Howard didn't feel the need to apologise for his part in the war, he took President Bush's side without question, as did every other country. America called on her friends to rally and join them in the "Coalition of the Willing" and they did, in spades.
But the US made a terrible mistake, and so did we.