Former Prime Minister Sir John Major has criticised successor Tony Blair over the Iraq war, saying his main motive appeared to have been regime change.
Sir John said the handling of the 2003 invasion had done more damage to trust in the UK political system than the expenses scandal, and the Chilcott inquiry was raising further questions about the Government's conduct.
The Tory ex-premier told BBC Radio 4's Today programme he wanted to know whether the Cabinet had been aware of doubts about Saddam Hussein's threat before the decision to take military action.
"The suspicion arises that this was more about regime change than it was about weapons of mass destruction," he added.
Sir John said that in the mid-1990s aides to US President Bill Clinton had raised the idea of regime change in Iraq with UK officials.
They replied that any attempt to remove Saddam had to be legal and viable.
"There are many bad men around the world who run countries and we don't topple them and, indeed, in earlier years we had actually supported Saddam Hussein when he was fighting against Iran," Sir John said.
"The argument that someone is a bad man is an inadequate argument for war and certainly an inadequate and unacceptable argument for regime change."
Sir John said he had trusted Mr Blair's claims about the danger Iraq posed, but was now not so sure.
"I had myself been prime minister in the first Gulf War, and I knew when I said something I was utterly certain that it was correct, and I said less than I knew," he said.
"I assumed the same thing had happened and on that basis I supported reluctantly the second Iraq war."
Mr Blair is due to give evidence to the Chilcott inquiry over the next few weeks.