Spytrap details how the defection of Vladimir Petrov in 1954 led, through various channels, to the clearing of Kim Philby of suspicion of being the Third Man by Foreign Minister, Harold MacMillan, in the House of Commons. This clearance gave Philby, the most celebrated and execrated master spy of the century, an extra eight years as an important KGB spy before he finally defected in Beirut to Moscow in 1963. Although Spytrap deals in some depth with Petrov in Australia, it concerns itself more with the impact that Petrov had in the attempted "smoking out" of Philby and the relationship between them. Features interviews with Malcolm Muggeridge, historian A.J.P. Taylor, as well as journalists Phillip Knightley and Murray Sayle.