A lorry driver will be jailed for causing the deaths of a family of four when he fell asleep at the wheel of his truck.

Ian King ploughed into a queue of stationary traffic in his 30-tonne low loader, on the A34, near Bletchingdon, north of Oxford.

The truck crushed a Peugeot belonging to Malcolm and Janice Dowling.

The couple and their sons, George, 11, and Richard, 16, who were travelling home to Lichfield, Staffordshire, from a family holiday in France, were killed instantly.

Tonight, 60-year-old King was warned by a judge that he would be going to jail when he is sentenced in the new year.

An Oxford Crown Court jury today unanimously convicted King, from Leicestershire, on four counts of causing death by dangerous driving.

He had claimed he had an undiagnosed sleeping disorder which had caused him to pass out behind the wheel of his HGV and that he had no recollection of the smash.

One senior police officer who was called to the scene of the crash on July 31 last year told the court it was the worst he had ever dealt with.

The Dowlings' Peugeot 307 was underneath King's lorry, which had crashed into two other cars before hitting them.

The Dowling family - left to right, Janice, George, Richard and Malcolm The Dowling family - left to right, Janice, George, Richard and Malcolm Another driver, Stephen Chance, spent three months in hospital after his neck was broken in the crash.

Tony McGeorge, defending, had argued during the case that King suffered from sleep apnoea, a respiratory condition that disrupted his normal sleep patterns.

As the condition was undiagnosed, King had no idea that he was in any danger of suddenly passing out, he said.

But medical experts said there was no reason why he would not have been aware that he was becoming sleepy.

John Price, prosecuting, had argued from the start of the four-day trial that for someone to continue driving while knowingly growing sleepier fell into the definition of dangerous driving.

King was remanded on bail until January 11 for sentencing.

Judge David Morton Jack told him:"The court's sentencing is subject to the guidance of the Court of Appeal and the Sentencing Guidelines Council and they indicate, in effect, the inevitability of a prison sentence.

"It would not be fair to leave you in any real hope otherwise."

After the case, police warned of the dangers of driving while tired.

Sgt Peter Jell, of Thames Valley's Roads Policing Operational Command Unit, said in a statement: "One thing that this trial has highlighted is the devastating consequences of driving while tired or fatigued.

"I would urge every driver to take note of this trial - and if they ever feel the need to continue driving while tired, think of Malcolm, Janice, Richard and George Dowling and stop and take a break."