A friend of mine has complained that a rear view mirror is now required for anyone walking on the Regents Canal towpath in London, because it has become a bicycle super highway. I think that is an exaggeration, although the towpath is well used by cyclists. As a regular towpath cyclist I always follow the London Towpath Code of Conduct of course, and it seems most other cyclists do too. The main requirement is to give "two tings" on your bell when coming up behind people to avoid unnecessary heart attacks. I think making a 'ting ting' noise might also be ok, but this is not mentioned. Cyclists do not have a legal right to cycle on the towpath, but it is officially allowed by British Waterways who allow responsible towpath cycling. In London you do not need a British Waterways Free Cycling Permit but this is required in some areas.