From:
http://en.wikipedia.org/wiki/Rights_of_ ... #Footpaths
FOOTPATHS
Right of ways and open access across land typically only extend to walking. So you don't have a right to cycle or ride a horse on a public footpath. However, it is not a criminal offence to do so, unless there is a traffic order or bylaw in place specifically. A land owner may pursue you for damages under trespass Law or obtain a court order Injunction banning you from riding on their land, if you persisted.
BRIDLEWAYS
A public bridleway is a way over which the public have the following, but no other rights:
to travel on foot and
to travel on horseback or leading a horse, with or without a right to drive animals of any description along the way.
Note that although Section 30 of the Countryside Act 1968 permits the riding of bicycles on public bridleways, the act says that it "shall not create any obligation to facilitate the use of the bridleway by cyclists".
BYWAYS
A byway open to all traffic, or BOAT, is a highway over which the public have a right to travel for vehicular and all other kinds of traffic but which is used by the public mainly for the purpose for which footpaths and bridleways are used. (United Kingdom Road Traffic Regulation Act 1984, section 15(9)(c), as amended by Road Traffic (Temporary Restrictions) Act 1991, Schedule 1).
RESTICTED BYWAYS
On 2 May 2006 the Countryside and Rights of Way Act 2000 reclassified all remaining Roads Used as Public Paths as restricted byways. The public's rights along a restricted byway are to travel:
on foot
on horseback or leading a horse
by any vehicle (e.g. bicycles, horse-drawn carriages) other than mechanically propelled vehicles (e.g. motorbikes or cars)
PERMISSIVE PATH
A permissive path, or permitted path, is a path (which could be for walkers, riders, cyclists, or any combination) whose use by the public is allowed by the landowner, but over which there is no right of access.
A permissive path is often closed on a specified calendar day each year, and is usually clearly signed as a permissive path. These are precautions to prevent any possible future claim of continuous public access along the path, which could result in it becoming designated as a statutory right of way.