There are a number of incorrect statements made on this thread. It's worth noting that he terms , 'footpath' (FP), bridleway' (BW) 'byway open to all traffic' (BOAT) and 'restricted byway' (RB) have legal definitions and the generic term to cover them all is 'public right of way' (PRoW or sometimes RoW).
<The definitive map stems from the second world war (you'd have thought they had something better to do, but there we go) and, although called the definitive map can be far from definitive - depending on how up to date the LA keep it!>
There were no Definitive Maps (DMs) of PRoWs until the National Parks & Access to the Countryside Act, 1949 placed a duty on local authorities to compile them. It was inevitably a long and complicated process. However, all county and unitary councils now have DMs which are kept up to date and are available for public inspection. Some can be consulted online by accessing the Rights of Way Department of the appropriate local authority.
<if a path crosses a field which is being prepared for a crop i.e. ploughed, the farmer does not have to reinstate the path till after the crop has been sown, which may take a few days.>
This is not so. The occupier of the land has to reinstate the PRoW whenever the surface is disturbed (e.g. by ploughing, harrowing, drilling etc) within 24 hours unless this is the first disturbance for a particular crop when two weeks grace is allowed. There is also an exception if it is not reasonably convenient to restore the surface within that time (e.g. adverse weather conditions which prevent machinery getting into the field). Failure to comply with this law is a criminal offence.
A PRoW can only be diverted by due legal process. The occupier of the land is under no obligation to waymark the diversion but it is in his own best interests to do so.
<The farmer does have to reinstate the path to a width of three feet....there is a legal time limit, but pragmatically, this can extend a bit sometimes.>
This is not entirely accurate. A footpath has to be reinstated to a width of one metre and a bridleway to two metres or to the legal width if this is mentioned in a statement attached to the Definitive Map.
<Signs/stiles etc, generally, are not the farmers responsibility but belong to the LA.>
Highway authorities have a legal duty to erect signposts wherever a PRoW leaves a road. They may also waymark PRoWs but are not required to do so. Many voluntary organizations such as the Ramblers' Association, walking clubs, amenity groups etc waymark PRoWs but may only do so with the permission of the occupier of the land. The maintenance of stiles and gate is the responsibility of the occupier of the land but the highway authority is required to reimburse 25 per cent of the cost.
<Oh, this is a complete nightmare for all parties....!!!!!!>
This statement is, in my view, hyperbole. There are occasional local difficulties but in my very extensive experience of exploring lowland England on foot, I rarely come across an intractable problem.
