>I>Yes, it is illegal. Isn't it illegal in the UK?

No, and never has been. Various stuff do do with prostitution is illegal - for example brothels, pimping, touting for trade in the street ("soliciting") and kerb-crawling by would-be customers. But the actual transaction isn't illegal on either side.

There's some talk about changing this set up - one possibility would be stuff like licensing brothels, another would be to keep the law as it is generally, but to make it a criminal offence for the customers.