20mph is not ridiculous it's the difference between injuring and killing. Like it or not motorists have to share the roads with pedestrians who have an absolute right to use them whereas motor vehicles are only used under licence. The majority of residents of inner London do not have cars. Historically motor vehicles are the interlopers on our roads. We need them, yes, but not everywhere and there is certainly no need to drive a private ( as opposed to commercial) vehicle in central London.