Tremor of Intent by Anthony Burgess
Denis Hillier is an aging British agent on his last assignment. His old school friend Roper defected to the USSR long ago, to become one of the evil empire's great scientific minds. Hillier must persuade, or force, Roper to come back to England or risk losing his retirement fund. However, he hadn't foreseen the obstacles between him and his mark. Mr Theodorescu, a fellow passenger on board the ship to Hillier's target, and his companion Miss Devi, prove both irresistible and dangerous. This morality tale of a Secret Service gone mad features sex, gluttony, violence, treachery, and religion. Tremor of Intent is a rare combination of the deadly serious and the absurd, the lofty and the lusty.