The first locomotives constructed by British Railways were of the Battle of Britain class, but the naming policy reverted to the West Country for Nos. 34091–34108. The final two locomotives were Battle of Britain class, No. 34109 "Sir Trafford Leigh-Mallory" and No. 34110 "66 Squadron". The result of the delay in completing was that the squadron crest for "66 Squadron" was never made, as the manufacturer had retired during the intervening period. Thus "66 Squadron" was the only Battle of Britain class member not to have a crest.