This type of crossing is an endangered species – because there aren't as many as there used to be; more than 1,000 having been removed in the last five years and replaced mainly by pelican/pedestrian crossings because people need lights to tell them when to stop and start or cross the road. Who needs eyes and a brain eh?!
Here's an article on the subject that appeared in the Metro on 31st October.
And here are some of my photos of black and white stripey things:
Bottom: Greek Street, St Mary Axe, Tooley Street, Acton