By Ben McPartland MURDERED Highgate schoolboy Martin Dinnegan runs for his life, just moments before being stabbed to death. This dramatic CCTV footage has just been released by police, following the conviction of Martin s killers last week. Teenager Jos

By Ben McPartland

MURDERED Highgate schoolboy Martin Dinnegan runs for his life, just moments before being stabbed to death. This dramatic CCTV footage has just been released by police, following the conviction of Martin's killers last week.

Teenager Joseph Chin, 16, was ordered to serve a minimum of 12 years after stabbing the 14-year-old in the back on June 26 last year.

Martin's murder came after violent clashes between his friends and a group of youths including Chin, earlier in the evening.

The former pupil of St Aloysius' College in Highgate tried desperately to run from his attackers, screaming "Please help me" at horrified passers-by.

The scenes in Holloway, just yards from Martin's home, were captured on CCTV, now made public for the first time.

Chin's friend Kevron Williams, 17, was also ordered to serve four years behind bars after being convicted of attempting to cause grievous bodily harm with intent.

Passing sentence at the Old Bailey last Friday, Judge Brian Barker told Chin: "This was a deliberate attack requiring a long chase with revenge in mind.

"This was really arrogant group violence and the result is totally unacceptable.

"It was an attack carried out without any regard to the standards and rules that we live by and no thought for the victim, his friends and his family.

"The fact is that this was a vengeful attack out of all proportion to what may have gone before and no mercy was shown."

At the time of the killing, Chin was the subject of a 12-month supervision order and was being monitored by the Youth Offending Team in Islington.

He committed his first offence when he was just 11 when he was caught carrying a snooker ball in a sock. The following April, he threatened a man with a hollow bar.

In September 2006, he was convicted of actual bodily harm after knocking a shopkeeper unconscious by kicking him in the neck when he was confronted about shoplifting.

But his attack on Martin was his most violent - stabbing the teenager four times, leaving him bleeding to death in his brother's arms.

Speaking after the sentencing, Martin's mother Lorraine Dinnegan said: "On behalf of our family and friends, we would like to thank all the witnesses who came forward and helped to get justice for Martin.

"We are just pleased that we have got what we have got today.

"We hope that the people who have been involved with Martin's murder will learn from what has happened to him. We hope they come out of it better people."

She also revealed how, just days before his death, Martin had written an essay about a man who was chased by a group of men and left for dead by the side of the road.

So far this year, 22 teenagers have been killed on the streets of London - 19 of them stabbed - while last year 27 youngsters lost their lives.

ben.mcpartland@hamhigh.co.uk