John Patrick Horgan (born 26 may 1929) is an British actor who played played Captain Gregg in 1965 in the musical Baker Street: A Musical Adventure of Sherlock Holmes with Fritz Weaver as Sherlock Holmes and Peter Sallis as Dr. Watson.
In 1975, he played Sir Edward Leighton in the play Sherlock Holmes with John Wood as Sherlock Holmes, then he replaced Wood as Holmes for a few weeks (see play) before being himself replaced by John Neville as the detective and going back again to his role of Sir Edward Leighton for 6 more months. The same year, Horgan played Sherlock Holmes in Canada in The Speckled Band: An Adventure of Sherlock Holmes with Owen Foran as Dr. Watson.
In 1990, he was Sherlock Holmes again in Sherlock Holmes and the Speckled Band with Geoff Garland as Dr. Watson, and in a TV commercial for Lennox Gas Furnaces with Alexander Sandy Marshall as Dr. Watson.
- 1965 : Baker Street: A Musical Adventure of Sherlock Holme (as Captain Gregg)
- 1974-1975 : Sherlock Holmes (as Sir Edward Leighton) with John Wood
- 1975 : Sherlock Holmes (as Sherlock Holmes)
- 1975 : Sherlock Holmes (as Sir Edward Leighton) with John Neville
- 1975-1976 : The Speckled Band: An Adventure of Sherlock Holmes (as Sherlock Holmes)
- 1983 : Dramatic License (as William Gillette / Sherlock Holmes)
- 1990 : Sherlock Holmes and The Speckled Band (as Sherlock Holmes)
- 1975 : The Hound of the Baskervilles (as Sherlock Holmes)
- 1975 : The Return of Sherlock Holmes (as Sherlock Holmes)