I find that the little cycle lane which goes along the edge of Tavistock Square in WC1 is incredibly dangerous. Cars turn across the cycle path without looking - all the time.
Now, they're digging things up too. And it's just ... chaos. Pedestrians are meant to go over to the other pavement, but of course they don't. It makes for quite a comic ride. I recorded me going through it - and apologies for saying "cyclists, cyclists" so many times - I've gone a bit mad. But this might explain why.