Dad's Army - Season 2 (1969)

Eager as ever, Captain Mainwaring takes charge of the HQ-instructed physical training. The men's wariness to 'strip down' for it was right, Pike's mum embarrasses everyone when she drops by. The military challenge follows in the person of Captain Ogilvie, who announces his professional troops will attempt to penetrate the Home Guard platoon's HQ by way of exercise.

The platoon have been told that at the invasion signal, the ringing of the church bells, they must meet up at one of two rallying posts, Godfrey's cottage or the Novelty Rock Emporium. When the bells sound half go to the one and half to the other. Jones has forgotten his helmet, and Godfrey lends him a German one, which leads to his being mistaken for the enemy and fired at. Godfrey's sisters shake a table-cloth out of the window and this is interpreted as a white flag of surrender until Warden Hodges explains that there is no invasion, it was all a mistake.

Walker gets his call-up papers; the platoon devise a series of ploys to avoid losing him to active service.