Timebomb

Fired from a top-secret Soviet nuclear base in the chaotic last days of the communist regime, a KGB security man steals a suitcase bomb, smuggles it out and buries it in his backyard. Sixteen years later he's going to put it on the market. It's as lethal as on the day it was manufactured - capable of effectively wiping out a major city.
Discarded, abandoned, resentful, the Russian will sell to the highest bidder - in this case, a Mafia gangster who has no conscience for the consequences. The exchange will take place in a remote sector of the Polish-Belarus frontier. The chance of it being intercepted will depend on the skill, and luck, of a small MI6 team, who have only the sketchiest idea of what's going on - and on the nerve of an undercover police officer who has infiltrated the criminal gang.