The British Ministry of Defense told Parliament that the surveillance drone had proven unable to cope with Iraq's heat and sometimes flew off course never to be seen again, The Times of London said Tuesday.
There was also the fact that the surveillance equipment was mounted to the aircraft's belly, requiring it to make a usually tricky and often rough landing on its back at the end of each flight.
The Phoenix had been used to provide targeting for British artillery in Iraq but was never sent to Afghanistan due to problems flying in thin air, The Times said.
The ministry's decision brings to an end a program that began in the closing days of the cold war and cost Britain about $430.2 million.
The drone has been replaced in Iraq by the Hermes 450.