British rarely refer to ketchup as ketchup, we almost exclusively refer to it as "tomato sauce".

I'm British, and I refer to ketchup as ketchup. This may be regional; I'm southern-English. I'd probably by default assume that if you said 'tomato sauce' you meant a generic tomato-based sauce, not the specific condiment Heinz &c make.

Also southern English, and this matches my understanding of the terminology. But yes, I believe usage does vary regionally.

I'm British and I've only ever experienced people calling it ketchup

I’m British, from the South East, and it was tomato sauce in my family when I was a kid, but now it is ketchup. There was a transition at some point fairly recently. English evolves easily.

I think you've nailed it. I'm was Essex/Kent born and raised, with East End of London heritage. It was always "tomato sauce", was very rare to hear it referred to as "ketchup".

or even worse, "Red Sauce"

Yeah, you hear that a lot in "greasy spoon" establishments, perhaps because there isn't enough tomato in the recipe to claim it as such?

> Yes, people make pasta sauce with it.

With tomato sauce? Really?

Yeah I don't think I've ever heard of that in Australia.

I know about ketchup and 'tomato sauce' as being essentially the same condiment, used on a hot dog or what have you.

I've never heard of someone using actual ketchup/tomato sauce condiment as a pasta sauce. Literal spaghetti and sauce (that we all ate as kids, don't deny it) from a can would taste better.

Apparently it's a thing here in Thailand, but given how most Thai places in western countries treat Thai food, Im not sure I have much place to tell them they're doing it wrong.