@Jahanara0What an awful experience for you. At least they left without a fuss.
@Kenneth12 I guess this situation could fall under:
14.3 If you feel that any Member you interact with, whether online or in person, is acting or has acted inappropriately, including but not limited to anyone who (i) engages in offensive, violent or sexually inappropriate behavior, (ii) you suspect of stealing from you, or (iii) engages in any other disturbing conduct, you should immediately report such person to the appropriate authorities and then to Airbnb by contacting us with your police station and report number (if available). You agree that any report you make will not obligate us to take any action (beyond that required by law, if any).
So, even though Jahanara maybe has no "proof", and although prostitution is legal in the UK, (while "keeping a brothel" {defined as more than 1 sex worker in a space} is not), the right channels have been followed per Airbnb's Terms vis-a-vis calling the police. Weird that they want you to contact the "authorities" then provide your police report # in the case of "disturbing conduct"...which is an awfully vague term and not necessarily criminal.
Sidebar question: If you allow your space to be used by sex workers, or even if you are unaware of it, can you, as a UK host, be charged with keeping a brothel? Yikes.
I haven't found the policy about authorized guests. Would be interested to see that, too.