Why Amsterdamers Love Bikes More Than Londoners

One explanation for the different attitudes goes back to WWII:

Occupying Germans stole thousands of bicycles from the Dutch when they seized the Netherlands, leaving them unable to transport themselves in the manner they were used to. In Britain, however, strict petrol rationing meant bicycle use rose considerably as, for many, it was the only way to get around. The actions of war meant that the Dutch lost their bicycles, but the British were forced on to them. As soon as the Brits had the opportunity to get off their bicycles they did, with car ownership increasing rapidly in the post-war years, and continuing to remain high.