Former deputy prime minister John Prescott has spoken of his guilt about the "illegal" Iraq War.
Writing in The Sunday Mirror, Mr Prescott said he will live with the decision made to invade Iraq and the subsequent "catastrophic consequences" for the rest of his life.
"A day doesn’t go by when I don’t think of the decision we made to go to war. Of the British troops who gave their lives or suffered injuries for their country," he wrote.
"Of the 175,000 civilians who died from the Pandora’s Box we opened by removing Saddam Hussein."
Mr Prescott expressed his "fullest apology" and accepted a share of the blame about how the Tony Blair government handled the war.
"In 2004, the UN Secretary-General Kofi Annan said that as regime change was the prime aim of the Iraq War, it was illegal," Mr Prescott added.
"With great sadness and anger, I now believe him to be right."
Mr Prescott said that in the period leading up to the war, he was concerned that any intervention had to have support of the UN Security Council and endorsement from parliament.
"Tony’s note to Bush with that devastating quote 'I am with you, whatever' was all the Americans needed to go in, without UN support," he said.
Mr Prescott also criticised the way Tony Blair ran his Cabinet, saying ministers were given too little paper documentation to make decisions.
The recent publication of the Chilcot Inquiry into the Iraq War delivered a scathing indictment of Tony Blair's decision to launch an invasion, labelling the six-year conflict unnecessary and disastrous.