A LORRY driver who killed a motorist after dozing at the wheel walked free from court because the accident was caused by a sleep disorder.

But the family of the 25-year-old victim said they were struggling to accept the decision to acquit Clitheroe HGV driver Colin Wrighton.

Mr Wrighton, 53, of Mitchell Street, had been charged with causing the death of Joseph Tobias Tweddell by dangerous driving on the M62 on August 8 last year.

His 35-tonne lorry ploughed into Mr Tweddell's Nissan Micra by the Rocket Interchange, Liverpool, as the young web designer made his way to work.

But it was only discovered after the accident that Mr Wrighton suffers from sleep apnoea, a condition that restricts airflow during sleep and prevents air from entering the lungs.

Sufferers wake repeatedly through the night without knowing it and are chronically fatigued the following day.

Liverpool Crown Court heard that Mr Wrighton had now contacted the DVLA of his own accord and his HGV licence had been rescinded.

No evidence was offered against him and Judge David Aubrey, QC, recorded a not guilty verdict.

But after the case, Mr Tweddell's father, Nic, of Martindale, near Penrith, Cumbria, said there was still confusion over why Mr Wrighton had been found not guilty.

He said: "We need it explaining to us.

"I would like to believe that Toby's death was an accident and avoidable, that would be easier to take rather than it being caused by someone's negligence.

"I'm not looking for someone to be committed of a crime if they did not commit one.

"But we had been expecting the trial of someone charged with death by dangerous driving and we don't understand what has changed.

"It appears that the judge has found that it was an accident."

The victim, known as Toby, was on his way to work in Liverpool from the home he shared in Sale with fiancee Jenny Crisp.

Mr Tweddell was freed from the wreckage and taken to Whiston Hospital but he had suffered "catastrophic" injuries and died about five and a half hours later, at 2pm.

Ian Harris, prosecuting, said that victim impact statements from Toby's parents and his fiancee were "heart rending".

He added that obesity was a clinical feature of apnoea and Mr Wrighton, who then weighed 20 stone, said that he felt tired most days and used to catnap when he felt sleepy while driving, which is a common practice among truck drivers.

He said: "This case may stimulate some wider public appreciation of matters such as this. So it may well be that something positive may emerge from such a tragic loss of life."

Mr Wrighton shook his head when Judge Aubrey discharged him from the dock saying: "I anticipate you may leave with some relief."

He nodded and wept when the judge added: "but still with a heavy heart."

Mr Tweddell implored road safety chiefs to learn lessons from his son's death.

He said: "I want to reach out beyond this driver to all those future drivers who may kill someone.

"Road death is a blind spot in our society. If 20 people die in a train crash it is a national disaster, yet statistically that many people die on our roads every two days."

A spokesman for the Freight Transport Association said: "One can have no sympathy for someone who falls asleep because they have not had enough sleep but if they have this condition they must take the greatest care when driving.

"It is a genuine problem but drivers are subject to strict restriction on the length of time they can drive as it is."

Mr Wrighton was unavailable to comment.