The ending (spoilers)
This only got a 9/10 from me because I felt the ending was lazy. I guess endings are the toughest part to write in a story. But arresting the main cast and covering the camera lens with your hand, knocking it over? I agree it was their first major film script and the Flying Circus show often had sketches that ended abruptly with no real punchline, but they could have come up with something better.
"I will not go down in history as the greatest mass-murderer since Adolf Hitler!" - Merkin Muffley