Former British 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.
Sir John said he had reluctantly backed the war because he believed what Mr Blair had said as prime minister.
But now, he said, big questions had been raised by the evidence given to the Chilcott Inquiry into the war.
He told the BBC the argument that Saddam Hussein was a bad man and must be removed was an "inadequate" one.
Sir John said it now seemed there were doubts before the invasion about whether there were weapons of mass destruction in Iraq.
In an interview with the Today programme on BBC Radio 4, he said he wanted to know whether the Cabinet had known about those doubts.
Mr Blair is due to answer questions at the inquiry in the next few weeks.