Popplewell
Popplewell was a Major in the British Army under Colonel Gubbins during World War II. He was eventually promoted to General and wrote Reminiscences of World War II, published in 1946.
In an alternate timeline in which Germany won World War II, Popplewell (who preferred to be known as Pop) became the leader of the British resistance. While at the Festival of Britain, he assassinated a Reichsinspektor General. He later watched as the Doctor's TARDIS was taken away by members of the Britischer Freikorps, then told the Doctor and Ace what happened, recommending that they visit Ma Barker's café.
The next day, Ma took Ace to the café (secretly a resistance HQ) where she again met with Pop and questioned the two of them about what had happened in Britain after the war, and learning of the rumoured Black Coven. Arnold then arrived at the café and, seeing Ace there, accused her of working with the Freikorps. Lieutenant Anthony Rupert Hemmings then raided the café, but before he could arrest them, the Doctor arrived with General Otto Strasser and claimed that the four were double agents working against the resistance. (NA: Timewyrm: Exodus)