Anthony Rupert Hemmings

Lieutenant Anthony Rupert Hemmings was an officer in the Britischer Freikorps in an alternate timeline. When two of his men, Privates George Brady and Sidney Harris, reported their encounter with the Seventh Doctor and Ace at the Festival of Britain, he decided to go look for them himself, thinking they were members of the British resistance. Informed by Arnold of their location, he arrested them, but they escaped. After failing to find them, Hemmings returned to HQ to find that the Doctor had been accepted by General Otto Strasser as the Reichsinspektor General, and was promptly made part of the Doctor's staff.

Convinced that the Doctor was deceiving them, Hemmings followed Ace when she was sent to contact the resistance and find out what had happened in Britain after the war. He led a Freikorps raid on Ma Barker's café, but before he could arrest Ace, Arnold, Barker and Popplewell, the Doctor arrived with Strasser, claiming that the four were double agents and that Hemmings had nearly ruined a delicate operation. Hemmings was arrested, and when the Doctor later offered to help him escape, he instead punched him and ran. While trying to get to Strasser he found the Doctor's TARDIS in front of him, and stepped inside, where he found the Timewyrm and agreed to become her servant. (PROSE: Timewyrm: Exodus)

The Timewyrm sent Hemmings (who believed her to be one of the Norse gods) to lure the Doctor into her trap. In a replica of 19th century Cheldon Bonniface created on the surface of the Moon in 1992, Hemmings posed as George, the landlord of the Black Swan. After the Doctor escaped from him twice, the Timewyrm decapitated his body for his failure, then sent his consciousness into the Doctor's mind. He took over the part of the Doctor's mind which was home to his third incarnation's personality, creating an idealised Nazi city. He imprisoned the Doctor and Ace when they arrived, but the Doctor and his past self sent a telepathic message to Saul, who worked with Emily Hutchings to draw Hemmings out of the Doctor's mind and back into his own severed head, killing him. After the Timewyrm was defeated and the church returned to Earth, the head was given a burial, the Doctor and Reverend Ernest Trelaw presiding over the ceremony. (PROSE: Timewyrm: Revelation)

Behind the scenes
Hemmings was given the first name of Anthony in Timewyrm: Exodus, but the first name of Rupert in Timewyrm: Revelation. His full name was given in Happy Endings.