One of the country's leading racehorse trainers has described the Ridgeway National Trail as an accident waiting to happen, because of damage caused by off-road vehicles.

National Hunt trainer David Gandolfo, who is based at Downs Stables in Manor Road, Wantage, said the ancient track had been ruined by off-road vehicles, making it virtually impassable.

He said the scenic route was rutted with deep troughs - some up to to four feet deep. The condition of the trail had hit an all-time low, and it was only a matter of time before someone was injured.

The Ridgeway is Britain's oldest road and stretches for 137km over the chalk uplands of the Chilterns, and the Berkshire and Wiltshire Downs.

Although the unsurfaced track is a popular route for walkers and horse riders, the western section - which includes Oxfordshire - is classed as a public by-way and is a favourite destination for four-wheel drive vehicles and motorcycles.

Mr Gandolfo, 62, who trains international race winners on gallops beside the trail, said: "There are enormously deep ruts which have left it effectively impassable to horses and pedestrians and to the emergency services.

"A pedestrian or horse could break a leg, and riders could be thrown. This is on top of the danger caused by the presence of off-road vehicles.

"I am not saying they should be banned, but there needs to be some compromise. It is an accident waiting to happen."

Oxfordshire County Council, which has joint responsibility for the track, supports a policy of voluntary self-regulation, encouraging off-road drivers to stay away when the trail is muddy.