During the 1950’s the world was shocked by the defection to the Soviet Union of Guy Burgess and Donald Maclean, highly placed officials in the diplomatic service. Years later with the web slowly closing around him, Kim Philby defected also. Although in line for the Number Two job in the British Secret Service, he was also a full colonel in the KGB, whom he had secretly served throughout his career. This excellent dramatisation recreates the factual evidence which stunned a nation