Three Minus Two — Donald MacKenzie

Journalist Hamish Hunter finds himself in possession of a film on which the fate of several people and the relations between two countries - Poland and Great Britain - depend. But who can he trust? His girlfriend, Wanda, daughter of a dracin Polish count, whose loyalties are more complex than they seem? An old friend in the intelligence racket? The authorities? Soon Hunter finds himself in desperation, hounded on all sides, and in a climax of nerve-racking suspense it becomes finally clear that no on is on any side but their own.