Smutty Thomas
From Tardis Wiki, the free Doctor Who reference
"Smutty" Thomas was a friend of Charles Cranleigh, who worked at Guy's Hospital in at least the early 20th century.
Biography
"Smutty" should have come down to play cricket on Cranleigh's side on 11 June 1925. However, he proved unavailable and sent a substitute doctor instead. The Fifth Doctor, who happened to arrive in the TARDIS on the Cranleigh Halt train station platform around the time the substitute was due to arrive, was mistaken for "Smutty" 's doctor friend, who failed to arrive because he missed the train. (TV: Black Orchid)