O2 have a number that you can forward spam messages to. I didn’t realise this, apparently there are a couple of other carriers to offer this service too.
I get an annoying amount of spam on my mobile. Replying STOP is useless - I’ve already fallen into that trap. It would be nice if I could restrict all phone msgs (and even msgs) to a white list - like you can on Skype. In fact, I’d probably pay for that service.