Melita Norwood
Melita Stedman Norwood (née Sirnis) (25 March 1912 – 2 June 2005) was a British civil servant and KGB intelligence source who, for a period of about 40 years following her recruitment in 1937, supplied the KGB (and its predecessor agencies) with state secrets from her job at the British Non-Ferrous Metals Research Association . Her KGB handlers gave her the codename "Hola". She was considered "the most important female agent ever recruited by the USSR."