Leeds Crown Court heard how Christopher Hill, 40, stabbed 18-year-old Robert Broadbent 25 times in the chest and throat on October 6 last year.

Hill, of High Royd, Lepton, had been driving around Huddersfield dealing drugs with Mr Broadbent before he drove to a car park in Aspley and carried out the fatal attack.

The court heard Hill blamed Mr Broadbent for a robbery at his home in 2006.

After the attack Hill bundled Mr Broadbent into his car and drove it into a pond.

A fisherman, who saw the incident, called police.

Hill denied the killing when he was arrested the following day, first saying there had been a car-jacking and later blaming a 15-year-old schoolboy who had been in the car but fled during the attack.

During the trial, six friends said Hill had told them he planned to get revenge on Mr Broadbent for the robbery.

It took the jury of two men and 10 women just under two hours to find Hill guilty of murder.

He was sentenced to life in prison. The judge said he would not be considered for release for at least 19 years.

Mr Broadbent had lived for a time in Holly Grove, Staincliffe, before returning to live at his mother's home in Lepton shortly before his death.