For years critics have complained that four-wheel-drive vehicles damage historic roads, churn up moorland, disturb farm animals and wildlife and spoil the parks for those seeking peace and quiet.
Officials of the Brecon Beacons National Park have taken their opposition further and launched a campaign to have the vehicles banned throughout national parks. Already moves are afoot to close roads to them in the Brecon park's 520 square miles in south Wales. The move will infuriate many owners of off-roaders, especially the estimated 10,000 who go "green- laning".
Gwyn Gwillim, chairman of the Brecon Beacons park authority and a farmer, said: "The four-wheel-drive fraternity say they have a right to use these roads. But by exercising their right they are interfering with the rights of walkers, horse riders and others who come here for quiet enjoyment.
"I want to take away their right to drive here. I was born and brought up in the park, and it grieves me to see these vehicles coming in and spoiling the countryside for other people. They call it a sport. It's not a sport. It's an abuse."
Mr Gwillim and members of the park staff are particularly concerned about the damage the off-road vehicles are doing to Sarn Helen, a Roman road that runs through the Brecon Beacons.
"This is an important piece of history, part of our heritage and these vehicles have made it into an appalling mess," he said. "Some of the drivers have said we should repair it, but how can you repair 2000 years of history?"
The Beacons' chief officer, Martin Fitton, and his staff have been holding a series of meetings with people in the area as part of the consultation procedure before drawing up the next five-year plan for the park. There are many complaints at them about off-road vehicles. Farmers are especially concerned. They say animals are disturbed and the vehicles are a particular nuisance at lambing time.
"It's very difficult," Mr Fitton said. "We are not talking about the cowboys who drive on to the open countryside where they have no right to be, but people with a legitimate right to use these routes. Some are green lanes, designed centuries ago for horse traffic, not cars, and something must be done to protect them. We have had limited closures on some of the roads, notably an access road called The Gap, banning motor traffic for part of the year. Now we are in the process of applying for a traffic regulation order to stop vehicles using Sarn Helen.
"It's very difficult striking a balance between the small minority who want to use these vehicles and the large majority who want quiet in the park. We are having consultations with representatives of the other parks who have the same problem. We don't yet know if they will all support a ban, but we do need to have a national debate to resolve the problem."
National Park officials fear the worst is yet to come. They believe that in about five years vast numbers of off-road vehicles which have never left the tarmac will move on to the second-hand market, and people who pick them up cheaply may want to start driving in the countryside.
Some of those driving off-road vehicles in the parks are foreigners. Sue Parrott, head warden in the Brecon Beacons park, was alerted to a convoy of 12 Dutch drivers a couple of months ago who ignored a sign and drove along a route that was closed for the summer.
"They were being led on a safari by a local man," she said. "We took their numbers and reported them to the police. Because they are back in Holland the police cannot do anything but we are hoping the man who led them will be prosecuted."
Professor Ian Mercer, secretary general of the Association of National Parks, said off-road driving was a problem in all nine upland parks. "It's even more worrying that if affects old historical and even pre-historical routes," he said.
In the Lake District, Bob Cartwright, the park's head of management, said the worst problems had been solved with the co-operation of the off- road-vehicle drivers. He saw grave difficulties with a blanket ban on any of the park's recreational activities. "It's all right when the drivers are members of groups and you have someone you can negotiate with. It's the reckless individuals who don't have any code or discipline that give us headaches."
Tim Stevens, information officer of the Land Access and Recreation Association, said its members would fight any suggestion of a total ban.
"National parks are supposed to be for all to enjoy, whether you walk in them or get your enjoyment from looking through a Land Rover window," he said.
"We have offered to help to repair some of the damaged routes in the Brecons but our offers have been turned down. Again and again we have asked to be included in the park's management process. We could help a lot by exercising peer pressure to control our members and ask them to stay away from routes that are sensitive or badly eroded. But all the Brecon Beacons parks people want to do is ban us. It doesn't make sense."Reuse content