In the 1950s, just after the end of World War II, the United Kingdom and its intelligence agencies found themselves engaged in a struggle against their new rival, the Soviet Union. One of the favourite ways through which the new Cold War was conducted was espionage, especially the so-called ‘HUMINT’; this expression, an acronym for ‘Human Intelligence’, denotes the methods of traditional espionage, i.e. that based on sending agents, double agents or not, into the field to gather information necessary for strategic planning. Consequently, the Cold War provides numerous examples of double agents caught up in this very dangerous game. The most striking case is that of Harold ‘Kim’ Philby, an educated and sophisticated MI6 agent, but in reality always attracted to Soviet-style communism; in essence, Philby was a traitor. Philby was actually part of a group of British agents who had defected and sided with the USSR, who had become known as the Cambridge Five, as all five had studied at Cambridge; it was also thanks to the discovery of the information they exchanged with each other that MI6 set out on Philby's trail. Nicholas Elliott, an agent who had an intense bond of friendship with Philby, was assigned to ascertain his compromise. In his later memoirs, entitled With My Little Eye, Elliott recounts how difficult it was for him to accept the betrayal not only of one of Britain's best intelligence agents, but also of the man he considered his best friend. In January 1963, Elliott joined Philby, who had been posted to Beirut to spy closely on Egypt. The two met: apparently Philby, as soon as he saw Elliott at his door, said: ‘I was half expecting you’. And it was here that Philby managed to escape, defecting for good to the Soviet Union. It is not yet fully understood how he managed to escape Elliott, but several reconstructions claim that Elliott let his friend escape in order to live the life he so desired.