Followup to the introduction of shared use at the start of the 1980s, guidance from the mid '80s in LTN 2/86, "Shared use by cyclists and pedestrians" (PDF) — their original emphasis:
2.1 Allowing cyclists even limited use of facilities previously reserved solely for pedestrian use can be contentious. But cyclists can be very vulnerable in the event of a road accident and it is essential that steps are taken to increase their safety. Clearly every attempt must be made to improve conditions for cyclists on carriageways, through improved highway design and maintenance, but there will be locations where, because of limitations of space or other unavoidable restrictions, allowing cyclists access to specific pedestrian facilities – such as footways and footpaths – is the only way of enabling cyclists to avoid serious accident risks on the carriageway….
2.2 Footways and footpaths are already extensively misused in some areas by cyclists riding illegally. A considerable amount of the concern which exists about allowing shared use is generated by such abuse…. 2.3 Where, at specific locations, a need is identified for cyclists to be admitted to existing footways or footpaths, their right to be there must be established by changing the legal status of the footway or footpath … When all or part of the width of a footway or footpath has been converted to a cycle track it should be clearly marked and signed and no impression should be given that there is a general permission to cycle on footways and footpaths…. It must be emphasised that there are no circumstances in which a general or widespread opening up of footways and footpaths to use by cyclists would be acceptable.