“Horse of Destruction”, Opening Titles

On these albums

Doctor Who: The Myth MakersDonald Cotton starring William Hartnell, Maureen O’Brien & Peter Purves · 2001Soundtrack

Doctor Who: Adventures in HistoryWilliam Hartnell, Patrick Troughton with linking narration by Peter Purves & Frazer Hines · 2003Soundtrack

Doctor Who: The Lost TV Episodes - Collection OneVarious Artists · 2010

Source: MusicBrainz recording 6e7c88c1-5c4d-48d6-aa5b-0d012557e3b3 (CC0).