Arthur Webley makes his sole appearance in the film when Sergeants Nicholas Angel and Danny Butterman visit his property to discuss Webley's trimming of hedges on his neighbour's property. Webley holds a shotgun in his arm and when Nicholas asks him if he has a license for it, Webley answers "I 'ave for this 'un."
Webley then reveals to the two officers that his shed is filled with illegal firearms, including a deactivated sea mine. He does not reveal how he acquired these weapons but claims that they're all just junk and don't work. The guns are then confiscated and held in the police station's evidence room.
Arthur's death isn't shown on-screen, but his body is discovered in a pit beneath Sandford's Callahoun Park where the Neighbourhood Watch Alliance have been hiding the bodies of all the "undesirables" they've murdered.