A cool, clean, lightweight fictional variation on the story of ""the fourth man"" in London who tipped off Soviet spies Kim Philby, Burgess, and Maclean. (See Boyle's non-fiction exposÃ‰, 1979, p. 1408.) In Barker's version, British agent Clive Floydd is wrongly suspected of being the traitor--so he drops out of sight, goes off to Scotland, and, now impoverished, returns to London to wander about in rags. While so wandering, however, Floydd spots Fransen, a notoriously dangerous, right-wingishly paranoid CIA agent. Is Fransen perhaps planning to assassinate the dove-ish U.S. President, now on a London visit? Floydd, much worded, calls his old spy-boss Emnie and passes on his suspicions--but soon Floydd is murdered, and his dying words to Emnie are enigmatic indeed: ""You and your wretched flower."" So, while Emnie struggles to convince the unflappable Prime Minister of the danger to the U.S. Prez, he is also trying to figure out the meaning of Floydd's dying words. Could it have something to do with the identity of the real ""fourth man?"" And could it perhaps have something to do with Emnie's wife. . . about whom there are secrets abounding? A neat, ironic diversion--which, however, inevitably suffers (as does Bryan Forbes' fourth-man novel, to be reviewed in the March 1 issue) from the recent unmasking of art-historian Blunt as the real-life mystery man.