A Dandy in Aspic Anthony Mann Laurence Harvey (1968)

Alexander Eberlin is a British spy. Only he isnt really Alexander Eberlin. His real name is Krasnevin and he is actually a Soviet spy. Hes a double agent but his loyalty is to the Russians, not surprising since he is a Russian. Now the British have handed him a rather awkward assignment. They want him to kill a top Russian agent, a chap by the name of Krasnevin. He himself is the man he has been ordered to kill.