https://delishably.com/meat-dishes/The-Mystery-of-Brown-Windsor-Soup
In October 1956, an episode was broadcast with the title The MacReekie Rising of ’74. Rebellious Scots attacked the Tower of London by firing porridge at the garrison.
The character Neddy Seagoon (played by Harry Secombe) says “Very well then. If the Scots want to make it a war on nutrition, we have an English dish in our armoury twice as deficient in calories as porridge and twice as deadly.”
Major Dennis Bloodnok (Peter Sellars – yes, that Peter Sellars): “Seagoon, you’re not going to fire ...”
Seagoon: “Yes, Brown Windsor Soup.”
The dish cropped up frequently as a running gag in later scripts. One such was when a character declares “I successfully changed all the Chinese back into Englishmen by giving them injections of Brown Windsor Soup.”