John Le CarrÃ‰ and Frederick Forsyth don't mix--or at least not very effectively. So this smartly written blend of Le CarrÃ‰-style espionage (moody ""mole""-suspicions) and Forsyth-style countdown (brink-of-WW III technology) becomes less and less involving as it alternates between two very different sorts of suspense fiction. The first 100 pages or so are splendid. It's the late 1980s--and captured British agent Conroy, tortured and interrogated in Moscow, now returns to England: he's been swapped by the Russians for their spy Garnett (a ""mole"" who was recently exposed and imprisoned). But Conroy, who's sure that he was betrayed by colleague Karen, now finds himself under suspicion. UK spymaster Goss, a zestfully foul fellow, subjects Conroy to bewildering grillings at the spy ""Home."" Did Conroy crack under the USSR third-degree? (Conroy's sure he didn't.) Did he in fact fake his own capture/imprisonment? Also: what about Karen, who protests her innocence as vehemently as Conroy protests his? Mutual suspicion abounds, then; either Karen or Conroy--or Goss!--must be a traitor. And the stakes rise sharply when the Russians execute a brilliant propaganda coup (they expose NATO's new ""Launch on Warning"" nuclear-missile setup), which means that there's a major intelligence leak somewhere. So, to clear their own names, Conroy and Karen--still wary of each other (though bedmates)--set out to find the leak, with grudging aid from Goss; and while still suspicious of Goss, they focus chiefly on the Intelligence computer system, whose mastermind (a top suspect) has recently retired. Unfortunately, however, this investigation soon becomes slow and talky. (In a rare spot of action, Goss is near-fatally attacked.) And, meanwhile, the world is teetering--not very convincingly--on the brink of nuclear war. . . since, as Conroy finally deduces, the blackmailing USSR has tapped itself directly into all NATO Intelligence. Neither the missile/satellite/computer material nor the international politics is especially well-done here; both detract from the low-key espionage. But, even if Crisp (The Gotland Deal, The Odd Job Man) dilutes the impact of his central story with those doomsday-scenario trappings, this remains an above-average spy tale; and its virtues--strongly acerbic characters, lean atmosphere, dark-edged prose--should carry many readers through the more contrived or flimsy moments.