Prime Minister Tony Blair of Britain went to war alongside the United States in Iraq in 2003 on the basis of flawed intelligence that went unchallenged, a shaky legal rationale, inadequate preparation and exaggerated public statements, an independent inquiry into the war concluded in a report published Wednesday.

The long-awaited report by the Iraq Inquiry Committee, led by a retired civil servant, John Chilcot, takes up 12 volumes covering 2.6 million words, four times longer than War and Peace, and took seven years to complete, longer than Britain's combat operations in Iraq. It concluded that Blair and the British government underestimated the difficulties and consequences of the war and overestimated the influence he would have over President George W. Bush.