Stuart Nicholson and his son Connor died on the A66

Gerald Grange, 51, from Stockton, admitted two counts of causing death by dangerous driving on the A66, near Appleby, Cumbria, in June 2003.

Stuart Nicholson, 44, and his son Connor, six, from County Durham, died.

On Thursday, London's Criminal Appeal Court reduced his sentence to three and a half years.

Mr Nicholson, from Wheatley Hill, near Peterlee, was travelling home from the Appleby Horse fair, when the accident happened.

Judge James Paget QC, who was sitting with Lord Justice Hooper and Mr Justice Silber, described the case as "tragic".

Mr Nicholson, who was wearing a fluorescent jacket and walking the horse, was killed instantly with his son.

In also cutting Grange's driving ban, the judge said the purpose of disqualification was not to punish, but to protect the public.

'No explanation'

Grange, who had driven for many years, had a good driving record apart from two speeding offences.

Judge Paget said the caravan was painted bright yellow, there was bright sunlight and the road conditions were dry.

Measurements taken after the accident showed the caravan would have been in Grange's line of sight for about eight seconds, given the speed he was doing which was about 53mph.

"There is simply no explanation why he did not see the caravan," the judge said.

Grange was of previous "impeccable" character and he was assessed as posing a low risk of re-offending.

Prisoners who receive a sentence of four years or more are eligible to be released on licence after they serve two-thirds of their term.

But if the term is less than four years - as now applies to Grange - they are eligible half-way through the sentence.