Britain broke international law when it invaded Iraq in 2003, its deputy prime minister at the time, John Prescott says.
A seven-year inquiry concluded last week that former British Prime Minister Tony Blair's justification, planning and handling of the Iraq War involved a catalogue of failures, but did not rule whether the war was legal.
Eight months before the 2003 invasion, Blair told US President George W Bush "I will be with you, whatever", eventually sending 45,000 British troops into battle when peace options had not been exhausted, the long-awaited British public inquiry said.
Prescott, writing in the Sunday Mirror, said he had now changed his view on the legality of the war and criticised Blair for stopping his ministers from fully discussing in advance whether the war would be legal.
"In 2004, the UN Secretary-General Kofi Annan said that as regime change was the prime aim of the Iraq War, it was illegal.