In January 1968, Sir Harold Adrian Russell 'Kim' Philby KCMG CBE, chief of the SIS retired after serving the Crown for twenty-seven years. He was also a spy of Soviet intelligence- the infamous NKVD and its successor the KGB. On May 11, 1988, Philby died peacefully in his cottage in Surrey, England. His obituaries in national papers read: 'A suave and charming patrician figure leading successfully British intelligence in the Cold War'; 'a man who outmaneuvered his Whitehall rivals and avoided scandals'. This is a counterfactual history for the eyes of the specialist reader of the history of British counterintelligence. We reconstruct key events and episodes taking into consideration that since 1951 Philby was at the helm of the SIS. Weekly he briefed the prime minister and, influenced foreign intelligence and strategy to the advantage of the security interests of Moscow. Note: This monograph requires prior knowledge of British counterintelligence history. about the author: James Henderson devotes his time in archives and, feels books on intelligence and secret services have to be intelligence products. He adores reading research monographs and PhD theses. Indeed the research passion of early career researchers/academics boosts historical knowledge, especially on intelligence/espionage. While writing this monograph he had been listining to 'Philby' (1979) by Rory Gallagher.