Clive Dunn
From Tardis Wiki, the free Doctor Who reference
Clive Dunn OBE (9 January 1920-6 November 2012[1]) appeared as Doctor Fotheringown (a parody of the First Doctor) in the It's a Square World sketch The Doctor's New Invention. He was best known for playing Lance Corporal Jones on Dad's Army.
The sketch was later featured on the Doctor Who DVD The Aztecs: Special Edition.