“Kim Philby, Britain’s most notorious cold war traitor, told an audience of East German spies after his defection, that he was able to avoid being rumbled for so long because he had been “born into the British governing class.” So says the Guardian – His exploits, along with those of Burgess, Blunt, and Maclean make for dramatic reading. Known as the Cambridge Spy ring, it turns out that they may have been influenced and possibly led by a woman, Edith Tudor-Hart. Documents declassified after 50 years reveal that Edith was under round the clock surveillance. “The MI5 files detail the way in which the agency’s close scrutiny of Tudor-Hart’s life…