What happens in a Tube station when all the passengers have gone home? Why do Tube workers carry cards about rat piss? And why isn't standing on the right of an escalator necessarily a good thing? Londonist finds answers on our latest nocturnal investigation. Some of London's busiest Tube stations are in a mess. Missing tiles and chicken-wire cornices are a familiar site, especially at King's Cross and Leicester Square. It's a case of......

Londonist likes to breathe. This Londonist is pneumatically challenged, and so she is especially fond of a good puff of the invisible stuff. So when the invisible stuff becomes visible, and London is shrouded in an ominous sulphurous blanket, we either stay indoors, or wander around looking like Darth Vader, with one of those terribly fetching mouth and nose masks that cyclists wear. Various bods are meant to monitor air quality, but it seems to......