"It will be ugly and embarrassing,” Biddle told Britain's Sunday Times, predicting British casualties from stepped-up use of car bombs, ambushes and rocket-propelled grenades.
Biddle's comments concur with British military estimates that withdrawal could cost the lives of 10 to 15 soldiers. An unnamed British senior military officer predicted Britain's involvement in Iraq will be seen as a "major blunder" in military history.
Prime Minister Gordon Brown has told Bush no decisions about withdrawal will be made until after Petraeus delivers a progress report to the U.S. Congress next month, The Times reported.
Notable deaths of 2014 [PHOTOS]