I think it may have been a podcast of Rick's where I heard him talk about the differences t areas in London and (as us here know) it's best to learn before you go...
He spoke of an area where as he puts it, beautiful girls lure unsuspecting tourists in for a drink where they find themselves having to pay $100 and the "doors have no handles" so they are trapped.
Where was he talking about? A specific street? I'm not worried, honestly I thought it would be funny to see the area (in daytime).