Butterflys wasn't a safe place.
The building was falling apart, damp, bad wiring, loose carpets, accessed via an unlit fire escape.
Some of the girls were obviously volunteers, but some may not have been: some were EE, collected/delivered by pimp boyfriends in their german pimpmobiles every day.
There'd been a string of complaints about the place - it was on a high profile street and the related drunken antics caused a lot of problems for neighbours. The police had been looking to close if for a long time - she made it easy for them
The police can very very easily close any brothel they choose to immediately, there is no need to be looking to close it for a long time. Send a copper in posing as a punter and once he gets offered a sexual service that's all that's needed to be able to nick the pimp IF they can locate them, plus anyone else helping to run the place by answering the phone booking punters in for example. And in fact the law about brothels is a sexual service doesn't have to be offered, however for conviction purposes better to have that in evidence. Then once convicted POCA and HMRC could have their go against the pimp.
Its why the police don't do so with many more brothels that is the unanswered question, all are illegal obviously but the top cops choose not to enforce the law.
There are 2 types of pimp, 1 who coerces/forces and maybe traffics women to be WGs against their free will, or with the promise of a non sexual job which is the lure but a lie. And all such pimps should get done and given a mandatory life sentence. Then there are pimps who are pimps to WGs who choose to work for them, the reasons some WGs choose to do so are obvious to me. An EE WG from a poor country couldn't possibly afford to rent a premises in my area, or have the required references so they work for a pimp who provides the premises and lays their punters on for them. These are sometimes ex-WGs of the WGs nationality or even still WGs who rent out a room or rooms aspiring to be a pimp though there may be a Sergei figure pulling the strings with them all. In exchange the WG agrees to pay the pimp an agreed cut of her punts. Some EE WGs come here for an intensive 6 week period then go back home for a couple of weeks or more, for some of them paying a pimp an agreed cut is worth it to them. Even if they pay the pimp a lot they could well still be making much more money than they could at home.
Over the years I have spoken to many Brit WGs as Indies who said they used to work for a pimp and at that time it suited them as all they had to do was turn up as agreed, no getting punters themselves, it was all done for them. Those WGs then decided they could make more by going Indie so tried it to see how they got on, and some never looked back. Sadly pimps have always existed in punting and that wont be changing anytime soon. Its for the police to enforce the law that's the only sure way to reduce pimps but the will isn't their with some top cops.