The three continued to kick Ian Page when he had collapsed

Ian Page, from Neasden, north London, was with friends on Edgware Road, in nearby Colindale, when he was attacked.

Andre Campbell, 24, and Jermaine Yateman, 19, were convicted of murder while Lloyd Henry, 20, was found guilty of manslaughter at the Old Bailey.

All three, from north London, carried out the attack in November last year.

Four days after the assault, which was caught on CCTV, Mr Page died of severe brain damage.

In a victim impact statement his father, Kenny Page, said the family went "through hell".

Mr Page's mother said: "When my son's life was taken, part of my own life was taken as well."

The spark that caused the flare-up was never properly identified but on any view it was pretty inconsequential Judge Brian Barker

Sentencing the three Judge Brian Barker described the attack as a "brutal and totally unnecessary death".

He said: "What we have seen on that CCTV is chilling and it is scary.

"This was selfish, thoughtless, group violence. It was deliberately continued when there was no possible danger. It was unwarranted and it led to catastrophe.

"The spark that caused the flare-up was never properly identified but on any view it was pretty inconsequential."

During the trial the court heard that when Mr Page bumped into Campbell, he resorted to some "shouting and posturing".

He then went into a kebab shop and minutes later the three chased off Mr Page's friends and cornered him.

The three also robbed Mr Page of his gold bracelet

They then kicked him until he collapsed.

The gang returned soon after to steal a gold bracelet from Mr Page and launched another attack on him.

The court heard that all three had previous convictions for various offences of theft, threatening behaviour and assault.

Campbell, of Stockford Avenue in Mill Hill, and Yateman, of Booth Road in Colindale, were ordered to serve a minimum term of 15 years.

Henry, who is Campbell's half-brother and lived at the same address, was given an eight-year sentence.