It's Ding Day!
see the DG for an excellent piece about this establishment. But the story is, today is Ding Day! Transport for London, the LCC and even Time Out have all listed it as an event, the idea is create a friendlier vibe during rush hour by encouraging riders to greet each other with a 'ding' of their bells. So if you hear the streets of London ringing a little more than usual, you know what's going on.