Played by John Le Mesurier
Mainwaring's second-in-command, both in the bank and in the Home Guard, Sergeant Arthur Wilson is, in fact, socially superior to Mainwaring being educated at public school and a Captain in WWI. With his soft-spoken, unassuming and slightly dreamy nature, he's well-liked and happy to play second fiddle, but he's not above quietly questioning Mainwaring's judgement from time to time.
CATCHPHRASE: "Do you think that's wise, Sir?"