Mycroft Holmes

Mycroft Holmes was the brother of Sherlock Holmes and an ally of Bernice Summerfield. (BFBS: The Adventure of the Diogenes Damsel)

Biography
The Seventh Doctor, Ace and Benny met Mycroft while he was in the employ of the British government. (NA: All-Consuming Fire)

In 1916, Mycroft was working for the British government during World War I. (IW: The Found World)