A military adviser to the US has warned that British troops face an "ugly and embarrassing" withdrawal from the southern Iraqi city of Basra in the coming months, according to a British newspaper. Stephen Biddle, of the Council of Foreign Relations and a member of a group that advised US Gen. David Petraeus in 2006, told Britain's Sunday Times newspaper that coalition forces were no longer in control of the city. "I regret to say that the Basra experience is set to become a major blunder in terms of military history," Biddle was quoted as saying by the newspaper. "The insurgents are calling the shots ... and in a worst case scenario will chase us out of town." Britain is due to hand over formal control of Basra to local forces in the next few months, but is yet to set a formal date.