On 15 June 2009, the then British prime minister Gordon Brown announced that Chilcot would chair an inquiry into the Iraq War, despite his participation in the discredited secret Butler report. Opposition parties, campaigners and back bench members of the governing Labour Party condemned the decision to hold the inquiry in secret and its highly restrictive terms of reference which would not, for example, permit any blame to be apportioned.
In 2015, Chilcot was criticised as the Iraq Inquiry remained unpublished after six years. The head of Her Majesty's Civil Service Sir Jeremy Heywood said the inquiry had repeatedly turned down offers of extra assistance to help speed up the report. On 29 October 2015, it was announced that the inquiry would be published in June or July 2016.
The report was published on 6 July 2016, more than seven years after the inquiry was announced. The report stated that at the time of the invasion of Iraq in 2003, Saddam Hussein did not pose an urgent threat to British interests, that intelligence regarding weapons of mass destruction was presented with too much certainty, that peaceful options to war had not been exhausted, that the United Kingdom and United States had undermined the authority of the United Nations Security Council, that the process of identifying the legal basis was "far from satisfactory", and that a war was unnecessary.
He is currently[when?] president of Britain's independent policing think tank, The Police Foundation.