Offenders include the Government, which has planned motorways without allowing any means, such as bridges or underpasses, for people to follow important old paths that have been obstructed by traffic.
Members of the association are planning to walk on many of these disputed paths on Sunday 27 September, which they call 'Forbidden Britain Day'. On certain ancient routes that should be open to vehicles they will be joined by people driving Land-Rovers and riding mountain bikes.
David Beskine, an officer of the association, said: 'Landowners' leaders praise the path network, but thousands of farmers and landowners regularly plough up, plant over or otherwise obstruct public footpaths. The Ramblers' Association is brimming over with dedicated footpath fighters who are determined to get all public footpaths reopened.
'We know that right is on our side. Parliament backs us, the law backs us. The courts and the public back us.'
In Cornwall, for example, the ramblers are drawing attention to paths which they say have been obstructed by two farmers at Colquite and Dupath, near Liskeard. Near Whitehaven, in Cumbria, a farmer has built a wall across a footpath and in another place a footbridge has been swept away and the land is now being claimed as private. Near Harwich, in Essex, a householder has obstructed a path by extending his garden into it.
All county councils have a legal duty to compile definitive maps which are an official register of public footpaths and bridleways. But all county councils do not put an adequate effort into this work, the association says. A large area of Kent near Tunbridge Wells has virtually no public access due to the failure of the county council to register ancient rights of way. Legal rights of way are missing from the definitive map of Hertfordshire in the area of Broxbourne, and from the Suffolk map near Stowmarket and Waveney.
Ramblers are also claiming a right to roam beyond footpaths where the land is uncultivated. In Scandinavia, the public has a legal right to walk in such areas. With this in mind, ramblers are walking on Big Moor in the Peak National Park, an uncultivated area of high moorland, where owners are wanting to keep the land private. They are also seeking a right to roam in Coombs Valley, Derbyshire, and the Forest of Bowland, Lancashire.
'We will not allow the law-breakers, the negligent local authorities, or anybody else to get away with robbing the public of the delights of a country walk,' Mr Beskine said. 'This is our common heritage, treasured by local people throughout Britain, and now being fought for by those very same people with the full backing of the Ramblers' Association.'