Percy Blakeney

 was Peri Brown's fake husband when they visited the 18th century. He was ill and the Sixth Doctor posed as the Scarlet Pimpernel whilst he recovered. He was an alien who told the Doctor and Peri that he was escaping the grief of the Genocide of his people by the Z22 and used the stories to do this. He had a transmat hidden in the cellar which returned him to his home world. In fact he caused the genocide himself, because he was loosing power. He tried to tell the Doctor that he had atoned for his sins. He was stabbed by Donat and almost died. The Doctor but him in a coma to save his life, and he was trialled in absentia and imprisoned. (AUDIO: Plight of the Pimpernel)