Showing Rogue Male by Geoffrey Household

An Englishman plans to assassinate the dictator of a European country. But he is foiled at the last moment and falls into the hands of ruthless and inventive torturers. They devise for him an ingenious and diplomatic death but, for once, they bungle the job and he escapes.

But England provides no safety from his pursuers - and the Rogue Male must strip away all the trappings of status and civilization as the hunter becomes a hunted animal.