The Iraq War was illegal, according to Lord Prescott, the deputy prime minister at the time of the 2003 invasion.
The Labour heavyweight used his strongest language yet to condemn Tony Blair's decision to take part in the Iraq War, a decision he supported at the time.
Lord Prescott's comments come just days after the publication of the long-awaited Iraq Inquiry report by Sir John Chilcot.
Writing in The Sunday Mirror the peer said: "I will live with the decision of going to war and its catastrophic consequences for the rest of my life.
"In 2004, the UN secretary-general Kofi Annan said that as regime change was the prime aim of the Iraq War, it was illegal.
"With great sadness and anger, I now believe him to be right."