It doesn't work, and i'm in the UK too. Bad actors simply ditch their LTD Co when they eventually get a small fine and some use it as a whitelist of active numbers to use. IIRC there was an idea about making directors of companies who flout this personally responsible, I wonder if this happened?

The USA has a similar solution. See https://www.donotcall.gov/ for details. Until fairly recently, it also worked pretty well. And still does for legitimate companies doing phone solicitation. (Excepting political parties, because they are exempt from the law.)

However spoofers who know that they won't be tracked back to the source don't care about do not call lists.

It doesn’t work. Only honest callers would follow this. In addition, looking up a number in there is paid which is less than ideal. The service itself is already an inconvenience to its “target market” (aka telemarketers or robocallers) so at least you should make it as easy as possible to use it.

I actually worked on a lawful telemarketing operation a few years back (don’t ask - desperate times called for desperate measures) and paying for TPS lookups was both a surprise and a huge problem.

The only reason it seems like it works is because the US is a much juicier market for the scammers so most don’t bother with the UK, but I still see people occasionally getting tech support scams or similar so clearly there’s nothing actually preventing them from spamming the UK - for now it’s just that the US is a bigger fish.