THREE thugs who murdered a teenager over a scrap of cannabis have been detained for life.

Kevin McLaughlin, 18, was kicked, punched and stabbed as he walked with his girlfriend near his home in Maryhill, Glasgow.

Knife-wielding John Struthers, 22, of Berneray Street, Milton, was ordered to serve at least 14 years before applying for parole.

Peter Cunningham, 23, of Tiree Street, Royston, was told he must spend a minimum of 12 years in custody.

Gary Sutherland, 16, of Ronaldsay Street, Milton, who was only 15 at the time of the murder on November 4, 2005, was given a minimum sentence of nine years because of his age.

All three had denied murdering Mr McLaughlin at a grassy area between Latherton Drive and Glenfinnan Drive in Wyndford, but a jury found them guilty.

At the High Court in Edinburgh, judge Lord Carloway told them: "This was a callous murder of a young man who had done nothing of significance to provoke the attack on him.

"It was a murder yet again prompted by the carrying of a knife or knives."

An earlier trial heard how Mr McLaughlin and a pal went to buy cannabis from Peter Cunningham's former girlfriend - and stole a small piece of the drug, which might have been worth £10.

She called Cunningham and told him what had happened.

Cunningham and his two accomplices, who were cruising the streets in a car, spotted Mr McLaughlin.

The three thugs chased him, punched him, then kicked and stamped on him as he lay on the ground. Mr McLaughlin was unable to defend himself when he was stabbed twice.

Doctors said either of the wounds could have been fatal.

Lord Carloway told the three killers: "Each of you must have participated in this, knowing knives were to be used or were being used in murderous fashion."

The court was told Mr Mclaughlin's father had visited his son's grave every day, while the teenager's mother had been too upset to come to court for the trial.