THE Yorkshire Dales' leading conservation group has launched a campaign to persuade the government to curb four-wheeled drive vehicles on its ancient green lanes.

At present a historical legal anomaly allows "wheeled" vehicles to use the picturesque lanes, many of which date back several centuries, said the Yorkshire Dales Society secretary, Mr Colin Speakman. But while those vehicles were intended to give horses and carts the right to use the lanes, the owners of today's high-powered 4x4 vehicles also believe they have right of passage under the wording of the law, he said.

"It has enabled well-informed pressure groups to lay claim to many ancient, unsurfaced tracks in the dales, both in the national park and the Nidderdale area of outstanding national beauty, for motorised access."

Now the society is pressing the government to change the law in its new Countryside Bill, to restrict motor access to green lanes by campaigning through the influential Association of National Park Authorities.

"These green lanes are one of the glories of the dales, part of the living archaeology of the area," said Mr Speakman.

He added: "Freedom and rights are emotive phrases but sometimes one person's rights trespass on other people's freedom. For many people who live in or visit the dales, freedom from noise, visual pollution, air pollution, danger and damage caused by motor vehicles is also a very precious right which is under increasing threat not just on tarmac roads but on tracks reserved for walkers, cyclists and horse-riders."

Mr Speakman added: "This is an issue which unites farmers, landowners, walkers, cyclists, and conservationists."

He said that a change in the law was long overdue.

Local highway authorities already have considerable powers to restrict use of green lanes by motor vehicles when they are damaging the highway or the environment, said Mr Speakman.

"The society isn't in the business of wanting to restrict anyone's enjoyment of the countryside, whether on foot, cycle or in a vehicle. But we support the principle that when conservation and recreation are in conflict, then conservation must take priority. The destruction of our green lanes is a classic example."

He anticipated "howls of protest" from the four-wheeled drive and trail-riding lobby and "orchestrated letters to the county council at any hint that their freedom to destroy and damage should be in any way curtailed".

However, said Mr Speakman, "our society and other conservation bodies also have a voice and we will make sure that it is heard. When it comes to conserving the landscape and special qualities of the dales, and opportunities for its quiet enjoyment, then the wishes of the majority must prevail.