Second Doctor
The Second Doctor is an incarnation of the Doctor, the protagonist of the BBC science fiction television series "Doctor Who". He was portrayed by character actor Patrick Troughton.
Midnight (Doctor Who)
David Troughton, cast here as Professor Hobbes, was a late replacement for Sam Kelly, who broke his leg and had to withdraw from the production. Troughton joined the rest of the cast in Cardiff with just two days notice. Now known for his stage work with the RSC as well as television, he is the son of Patrick Troughton, who portrayed the Second Doctor. He has had long association with the series since the 1960s, appearing as an uncredited extra in the Second Doctor serial "The Enemy of the World", as Private Moor in the Second Doctor serial "The War Games", and as King Peladon in the Third Doctor serial "The Curse of Peladon". He has appeared in the "Doctor Who" audio dramas "Cuddlesome", "The Judgement of Isskar", "The Destroyer of Delights", and "The Chaos Pool". He is unrelated to the director of the episode, Alice Troughton.