A Good Samaritan who came to the aid of an elderly motorist after he became stranded in flood water has criticised the council as sign diverted him towards the dangerous spot.

On Friday morning, an 86-year-old man, who is not from the area, was driving to Beaminster when he followed a diversion through Powerstock Common.

His car became stranded in water beneath the old railway bridge.

Rosie Britton, who lives in a nearby farmhouse, says she was alarmed to hear the man's cry for help.

"We opened the front door to find him soaking wet from the waist down," she said. "He told how, after following a diversion sign, his car had been stranded in flood water under the disused railway bridge and he had somehow managed to climb out of the car, rescue his dogs, wade out and, thanks to a passing rider, phone the police.

He was lucky to meet someone in such a remote spot and to get a signal there - many can’t."

Rosie invited the man in to keep warm and gave him a hot drink.

"By the time he arrived he was shaking with cold, having staggered well over half a mile in drenched clothes and waterlogged shoes," she said. "Had it been dark he would probably not have got here."

The man is not the first to have become stranded at the spot.

Rosie said: "Despite extensive repairs under the bridge, flood water still fails to drain away and, even before the onset of winter, this is not the first prolonged flood to block the lane recently. In past years, the road has sometimes been closed for weeks at a time despite repeated pleas to the council to solve the problem.

"Usually, when the bridge is flooded, a warning sign is placed higher up the lane informing motorists. The efficacy of the sign is slightly reduced by the fact that it is always left in place long after the road is passable again, but at least locals who suspect this know to approach with caution. This time, however, not only was there no warning but a diversion sign had been placed at the top of the lane - pointing towards the bridge. As a result, at least two cars had to be towed away in as many days."

Rosie has called on the county council's highways department to do more to prevent such incidents from happening again.

"Do we have to wait until someone dies there before the wishes of potential cyclists are seen as less important than the convenience of local residents who, year after year, have to drive two-and-a-half miles out of their way after every downpour? That's not to speak of the regular writing off of people’s vehicles and the risk to their lives."

Dorset Police confirmed they were called to assist the man after they became concerned for his welfare. Officers took him to Beaminster and recovery was requested for his car.

Dorset County Council has been contacted for a response.