Private Joe Walker is a fictional black market spiv (or "wholesales supplier", as he describes it) and Home Guard platoon member, first portrayed by James Beck in the British television sitcom Dad's Army.

Scriptwriter Jimmy Perry originally intended to play the part of Private Walker himself, but was advised against it by his co-writer David Croft.

This is owing to his many black market "business" connections and his ability to mysteriously conjure up almost anything that, due to the war, has become rationed or is no longer available in the shops.

[1] He is constantly on the lookout for opportunities to make a few bob, often attempting to sell black market supplies to his platoon comrades, and various influential people, often at high prices and from dubious sources.

This allergy was revealed in the episode "The Loneliness of the Long Distance Walker", in which he was conscripted, only to be discharged when it was found that corned beef fritters were the only rations left for the soldiers to eat.