Prostitution is happening and although there is a small amount of crime associated with it, that crime is magnified by the coverage it gets because of the salacious interest people get out of reading about it, there's more crime associated with football or pubs or something as mundane as travelling on public transport. A quick recap on what's been happening with crime in the UK one the last few years suggests that this kind of petty crime gets more and more overlooked and what we called "decriminalised", similar to the use of cannabis, not necessarily because governments have a liberal agenda, but because it costs money and resources to administer an ongoing, headline policy of stamping it out, there's no real votes in it and it's expensive, the only way it could be done is by monetising the prosecution of "offenders" similar to vehicle speeding crime, but how is that going to work, prossie-cams on street corners?
Even in the small city where I live and long before I ever punted, I have known of a number of brothels, one less than a mile from the main police station, there's no way the police wouldn't know about them, but they're no trouble, the only raids there has been has been on brothels populated by illegal immigrants, and it's the illegal immigrant part of it that interested the police, nothing to do with it being a brothel, in much the same way that they raid Indian restaurants, they're not against onion bhajis.