A TANKER driver who killed a father and son by ramming into the back of their horse-drawn caravan after last year's Appleby Horse Fair has been sent to prison for four years and banned from driving for five years.

Gerald Norman Grange, 50, pleaded guilty at Carlisle Crown Court to two charges causing death by dangerous driving.

Prosecuting counsel Frank Nance told the court the brightly coloured caravan - built of plywood and canvas on a metal chassis - disintegrated when Grange's 16-ton lorry ploughed into the back of it at more than 50mph.

Stuart Nicholson, 43, who was walking alongside his horse, leading it by its bridle, died instantly.

His six-year-old son Connor, who was sitting in the caravan painting in a colouring book, was also killed.

The horse was mortally injured and had to be put down by a vet.

The accident happened on June 10 last year just after the caravan had emerged from a slip-road onto the A66 at Coupland Beck, near Appleby, as Mr Nicholson and Connor were making their way back to their home to Caine Terrace, Wheatley Hill, County Durham, after staying overnight at the Appleby horse fair.

For some reason, Mr Nance said, Grange, who was driving home to Stockton-on-Tees on the inside lane of the dual carriageway, failed to see the caravan, even though on that stretch of road it would have been clearly visible from about 250 yards away.

Mr Nance said no one knew what caused the accident.

"It is simply a matter of the defendant not paying attention to where he was or what he was doing," he said.

"There is no explanation why - in the bright sunlight of an early evening, in dry and clear conditions and on an open carriageway - he failed to see and react to a small and bright yellow painted horse drawn caravan."

In mitigation defence counsel John Elvidge said Grange said the tragedy happened because of "a momentary failure to concentrate on the road ahead" rather than a prolonged course of dangerous driving.

"Mr Grange has suffered immense remorse and bears a profound sense of responsibility," he said. "The burden he will continue to carry is a very heavy one. It is very difficult for him to come to terms with an something for which he has no explanation."

Judge Paul Batty QC, passing sentence, said he accepted the Nicholson family might consider the sentence too lenient.

Outside court, Mr Nicholson's sister Margaret Naylor said the family had been prepared for such a sentence.

"We knew that whatever sentence he got would not be long enough so we were prepared to accept it," she said.

"It has been a horrendous year and we are pleased now that a line has been drawn underneath it."