Former Prime Minister Sir John Major has criticised Tony Blair's handling of the Iraq war and his presentation of the case for invasion in March 2003.
Speaking on Today, as part of a programme guest edited by Liberal Democrat peer Baroness Williams, Sir John said that he had supported the war because he believed what the Prime Minister said about weapons of mass destruction, but that this was now being called into question.
"The suspicion arises that this was more about regime change than it was about weapons of mass destruction," he said.
"The then Prime Minister Tony Blair may have known things that I don't know which may make things that seem curious fully understandable.
"What I do think is not understandable - the argument that Saddam Hussein was a bad man and therefore must be removed simply won't do.
"There are many bad men around the world who run countries and we don't topple them."