Oxfordshire's ancient Ridgeway could still be under threat from trail bikes and four-wheel-drive vehicles, claim the Conservatives.

They say rural lanes and byways such as the historic track which runs across the Berkshire Downs in south Oxfordshire could still be wrecked under new legislation.

County councillors voted earlier this year to ban motorists and bikers from using a 14-mile stretch of the trail between October 1 and April 30 each year to try to prevent the surface being churned up.

The Tories plan to try to alter the Environment and Rural Communities Bill to further restrict the use of rights of way by recreational vehicles.

Shadow environment secretary Oliver Letwin, and his agriculture and rural affairs colleague, Jim Paice, said they were concerned that a recent surge in applications to create rights of way for recreational vehicles could undermine the legislation.

Mr Letwin said: "We will be tabling an amendment which will oblige the Secretary of State to review all new applications -- favouring conservation and the interests of walkers and horse riders over recreational use by trail bikes and 4x4s.

"Any new applicant would have to prove that the byway they seek to create would not cause environmental damage or nuisance to the local community.

"Where this is possible, the Secretary of State must impose a traffic Regulation Order, banning non-essential traffic."