Jailed for life: Boy, 16, who stabbed 14-year-old to death 'over a dirty look'

A teenager was today  jailed for life after he stabbed a talented schoolboy to death while under a supervision order.

Fourteen-year-old Martin Dinnegan was stabbed in the back four times near his home in Holloway, North London, after two groups of youths clashed.

Martin was singled out after the groups exchanged 'dirty looks'.

He was chased by a gang and left dying in the street in June last year.

Joseph Chin, 16, who has a history of violent crime, was handed a life sentence with a minimum term of 12 years after he was found guilty of murder by an Old Bailey jury.

Another teenager, Kevron Williams, 17, was convicted of attempting to cause grievous bodily harm during the attack in June 2007, and was given four years in youth detention.

The judge yesterday lifted reporting restrictions identifying the underage killer and his accomplice.

Sentencing the pair, Judge Brian Barker, the Common Serjeant of London, described the incident as 'arrogant group violence', adding 'this was a vengeful attack out of all proportion to what may have gone on before.'

He said: 'The public have every right to be concerned about the increased growth of this sort of violence.

'It is a tragedy that this sort of triviality caused such a young man to lose his life and has caused enduring heartache to his friends and family.'

Killer Joseph Chin was handed a life sentence for stabbing Martin while Kevron Williams was convicted of grievous bodily harm

Chin stabbed Martin after being knifed twice himself during a series of flare-ups on the day.

The judge told him: 'This was a vengeful attack out of all proportion to what may have gone on before and no mercy was shown.'

Chin had a criminal record dating back to 2004, including the possession of a snooker ball in a sock and threatening a man with a hollow bar.

In September 2006 he was given a 12-month supervision order after kicking a shopkeeper unconscious when challenged for stealing some food from outside the store, and was still under the order when Martin died the following June.

Aftab Jafferjee QC, prosecuting, said teenagers are now prepared to use violence when showing off in front of friends.

He said: 'This is such a case, which leads from dirty looks to death in one hour.'

The trial heard that Martin had been on a bus when looks were exchanged with a rival group on bicycles.

Following another encounter when Chin received two cuts, Martin ran away and was chased along the street.

He was initially caught up by Williams, who punched him to the ground and stabbed him in the buttocks with a screwdriver, but then got up and continued to flee.

Tom Morgan, a witness who lived in the area, said he saw Martin running past him pleading: 'Please help me.'

These dramatic CCTV images show the 14-year-old desperately trying to escape his attackers

He saw a 'white-faced' Martin raise his hands as if to placate a youth who approached him on a BMX bicycle.

But the cyclist, Chin, then knocked him to the ground and pinned him down.

'Then I saw what seemed to be a stabbing motion rather than a punching motion four or five times in very rapid succession,' said Mr Morgan.

Martin, a pupil at St Aloysius College in Archway, lived on a local housing estate where there was rivalry with youths living on another estate.

Mr Jafferjee said he was 'entirely without blame during the final confrontation' and had in fact fled from the encounter.

The victim's mother, Lorraine Dinnegan, paid an emotional tribute to her son, saying: 'Martin was a charming, loving boy who has left us with cherished memories that will remain with us forever.

'The pain that Martin's death has caused for our family is indescribable. Life will never be the same, a piece of our heart has been taken.

'We as a family will never make sense of the unnecessary suffering that was inflicted upon Martin.

'It was extremely sad to be burying Martin at the tender age of 14.'