In Dad’s Army, Captain Mainwaring is often portrayed as a fool, but never as a coward. In the episode Asleep in the Deep, first shown in October 1972, the platoon and Hodges find themselves in real danger of drowning in a flooded bunker.
At one point they draw lots to decide who will be be at the head of a chain passing rubble from beneath a collapsed roof. Captain Mainwaring cheats to ensure that he joins warden Hodges in that dangerous position.
Perhaps he does it to demonstrate that anything Hodges is prepared to do he will do also, but it certainly shows that Mainwaring is no coward.