Kenneth Valentine
From Tardis Wiki, the free Doctor Who reference
Kenneth James Valentine (1921 – 1967) was an operative with Torchwood Three and partner of Charles Cromwell in the mid 20th Century.
He defected to the Soviet Union for financial reasons and was shot dead by Jack Harkness in 1967. Because of his defection, no records of his time at Torchwood exist. (TWN: Trace Memory)
