"Belt and braces" (UK) vs. "belt and suspenders" (US). I'm pretty sure the phrases have the same meaning, they just use a different word to refer to the thing that holds pants|trousers up.
And the word "suspenders" in British English means what Americans would call a garter belt, hence it sounding particularly odd over here.
The US usage is much kinkier
That is what I had in mind. I was also wondering what American call them so thanks for answering that.
Americans call bum bags fanny packs. Always raises a smile.