The parents of two schoolgirl friends killed in a motorway crash welcomed the conviction yesterday of the lorry driver responsible for their deaths.

Robert Murray was warned by Judge Paul Glenn at Stafford Crown Court that he faces prison after he was found guilty of causing the deaths by dangerous driving of 13-year-old Rebecca Casterton and her 12-year-old friend, Lauren Brooks.

They died when the car they were in was hit by Murray's 40-ton articulated lorry on the A38 at Clay Mills near Burton-upon-Trent, Staffordshire, in January this year.

The car was sent spinning over a central reservation, landing on its roof. Rebecca died at the scene and Lauren later in hospital. The two were pupils at John Taylor High School, Barton-under-Needwood, near Burton-upon-Trent.

Judge Glenn told Murray: "You have been convicted and I am sure your barrister has told you that it could lead to a prison sentence. I don't think it would be fair or just unless I know as much about you as possible."

Murray (51), of Summer Crescent, Wrockwardine Wood, Telford, had denied the charges. Sentencing was adjourned until January. Death by dangerous driving carries a maximum sentence of 14 years.

After the verdicts, the parents of both girls issued statements. Mrs Irene Corie, Lauren's mother, said: "We cannot find words that begin to describe how the loss of Lauren has devastated our lives.

"During a difficult and emotional week at Stafford Crown Court, it soon became apparent that at the time this tragic event took place, a professional driver failed to carry out his duties in an appropriate manner, as a result taking the life of our daughter and destroying our lives forever.

"While nothing can be done to bring Lauren back, we feel that justice has been done with the conviction of Robert Murray, for her loss. This is a tragic but all too familiar story of a driver failing to take appropriate care on the road."

Rebecca's father, Mick Casterton, added: "I am very proud of Rebecca and love and miss her dearly. To know that she was taken away by someone's incompetent driving is very hard to come to terms with."

The prosecution claimed Murray was distracted while driving his lorry and making a mobile phone call to his wife.

Martin Butterworth, prosecuting, said Mrs Corrie was driving her Renault Clio on her way back to Burton-upon-Trent after picking up the friends from an evening at a riding school.

The girls were in the back seat when Murray's lorry clipped the rear of the car, spinning it across the A38 southbound lane, over the central reservation and into the northbound section. The car landed on its roof then turned over on to its wheels.

Murray denied, in evidence, that he was using a mobile phone to call his wife. He said he had finished a conversation with her and put the phone on a charger under the dashboard.

He said he was driving at 55mph when he pulled onto the A38. He planned to pass the Renault but pulled in and clipped the car. He said he was "devastated" when he realised what had happened and thought he had hit a pothole.

In a statement by Mrs Corrie read to the jury by Mr Butterworth, she said: "I became aware of a lorry coming alongside me and could see the front of the cab beside me. I thought he was overtaking then the lorry seemed to go backwards behind me and I then felt a bang at the back of my car. I knew the lorry had hit us.

"The car was shaking and went out of control. It all happened so quick but it seems like it was slow motion. I think we somersaulted into the central reservation and we started to spin and went over the central reservation. I knew we were upside down then flipped over on to our wheels."