I think London is probably the worst place for it because people are fighting over inadequate road space. In MK there's almost none of it because of the provision of Dutch-style segregated cycle paths where there's plenty of space for everyone, though in the older areas where these aren't provided you do get a lot of pavement cycling because people are just used to the idea of cycling on the path rather than the road and it doesn't occur to them that there's any difference between a pavement (where cycling is not allowed) and a Redway or leisure path (where it is). Sometimes cycling *is* allowed on pavements in MK, in which case they are done with red tarmac making them also a Redway, as well as having characteristic yellow bollards at road crossings.
(MK has two levels of shared paths - a Redway, which has red tarmac, is supposed to be treated as a traffic-free country lane, cycling on the left and walking on the right and looking out for each other, whereas a Leisure Path, which typically has a loose gravel surface and is narrower, allows cycling but with priority to pedestrians).