Probably most successful female spy even. Born Ursula Kuczynski in 1907. From a whole family of spies--Jews of Polish origin. Married Englishman Len Beurton to get British citizenship. Came to Britain in 1941 to act until 1950 as controller of important GRU spies, possibly Hollis.
Escaped to East German in 1950. Received many Soviet awards (which leads people to believe she did control an very important spy like Hollis).