Lucas Seyton

Lucas Seyton, also known as the Fallen Angel, was a gentleman thief in 1930s London. Prior to this, he saw action in the air force during World War I with his friend Squadron Leader Paul Kettering.

History
In 1933, Seyton saved the Second Doctor from androids which were pursuing him. After learning that the Doctor's friends Jamie and Zoe were trapped in a house with other killer androids, Seyton and Kettering helped the Doctor rescue them. Seyton's memories of these events were erased by the Time Lords. (PROSE: Fallen Angel)

In August 1937, Lucas Seyton stole an original draft of William Shakespeare's Romeo and Juliet from the Palace Theatrical Museum in London, where he discovered another robbery taking place. He tracked the thieves to a club in Shanghai, owned by his old friend Mr Woo, and told him what he knew of them. (PROSE: The Shadow of Weng-Chiang)

Behind the scenes
Lucas Seyton is based on (to whom the Doctor compares him), created by  (to whom Fallen Angel is dedicated).