Who knew?

The story goes that Winston Churchill noticed that bricklayers at his Chartwell Estate wore a heavy boiler suit. Next he went to his shirtmaker Turnbull & Asser asking them to make a similar garment from a suit fabric. Winston Churchill was so thrilled with the result that he ordered a batch of siren suits in different fabrics.

The famous prime minister called his one-piece suit a “romper suit”. People dubbed it a siren suit though. When the sirens in London warned about bombers during WWII, Winston Churchill and citizens of London would swiftly put on a lightweight one-piece suit, “the siren suit”, before going to a bomb shelter.

https://sartorialnotes.com/2017/02/01/churchills-romper-suit-siren-suit/

https://therake.com/stories/style/the-overall-effect-and-call-of-the-siren-suit/