A THUG who stabbed a teenager through the heart in an unprovoked murder on his 18th birthday has been locked up for 13 years.

At the High Court in Glasgow, judge Lady Dorrian ordered Graham Campbell, 17, to be detained without limit of time.

Campbell was just 16 when, armed with a knife, he attacked Craig McCulloch as he and a friend walked along Cathcart Road, Glasgow, just before midnight on April 30 last year.

Craig was stabbed through the heart and medical staff tried in vain to save him.

Lady Dorrian told Campbell: "An innocent and unarmed young man lost his life and his family will be devastated.

"The punishment part of your sentence I set at 13 years. This does not mean you will be automatically released at the end of that period.

"You will have to satisfy the parole board you are no longer a danger to the public."

Campbell, who is detained in secure accommodation in Montrose, Angus, was convicted after trial at the High Court in Paisley of murdering Craig.

Co-accused Allan Wright, 16, of Peat Road, Pollok, who was originally also charged with Craig's murder, pleaded guilty after the first day of the trial to committing a breach of the peace by brandishing a knife.

The court heard the murder took place as Craig, who was celebrating his 18th birthday, and a friend walked back home from a pool hall.

Wright, who gave evidence against Campbell, was put on probation for two years and ordered to perform 240 hours' community service.

As Wright was sentenced, Campbell and members of his family in the public benches shouted "grass" at him.

Peter Gray QC, defending Campbell, said: "This need not have occurred had it not been for Mr Campbell taking a knife from his home.

"The death of Craig McCulloch was an utter tragedy and that is clearly recognised by Graham Campbell.

"The danger that knives represent and the tragedy they cause are clear to him now."

Margaret Breslin, representing Wright, said: "He has brought shame on himself and his family. His behaviour that night was reprehensible. He was just 15 at the time."