Oh, man, I hate most London drivers. We live right in front of a zebra crossing, and I always walk hesitantly into it, because people FLY through it. And definitely, as sweetpeach said, they are still flying on the other side while I'm crossing the first half. And the speeding down the side streets gets me too. The roads are narrow, there are ton of familes, so little kids, strollers, etc. There's no need to go that fast!
I find if I have the option to cross at a light, that's what I do. I used to like zebra crossings, but the one in front of my house almost seems like an afterthought to drivers.