London is getting there, slowly! There are some excellent examples of well-designed, well-used cycle infrastructure such as the new(ish) Cycle Superhighway along the Thames Embankment. This will hopefully serve as a model for future infrastructure.
In general, traffic speeds are low in London and there are lots of quiet side routes that are well suited to cycling. We’re no Amsterdam, but cycling is certainly much more popular and visible than it was 5-10 years ago.
London is unpleasant and stressful, but as Reason077 says, traffic is slow. Compared to the American cities I’ve seen, though, it’s second only to Davis.
In general, traffic speeds are low in London and there are lots of quiet side routes that are well suited to cycling. We’re no Amsterdam, but cycling is certainly much more popular and visible than it was 5-10 years ago.