A teenage killer was jailed for at least 18 years on Friday for stabbing a doctor’s son to death at the climax of a postcode war.

Jeffrey Lartey, 17, was part of a 20-strong mob who set upon Ailton Campos De Oliveira as he cycled home from a party.

Ailton, 16, was targeted as part of a bitter rivalry between three notorious street gangs responsible for a shocking catalogue of crimes across Newham. He was beaten with baseball bats and metal bars and fatally stabbed because of his perceived links to the Custom House street gang.

The attack was revenge for the murder of Stephen Lewis, 15, who was stabbed to death at an anti-knife crime disco 18 months earlier.

Stephen’s best friend Jerelle Wilson-Moonie, 19, from Romford, was convicted of murder alongside Lartey. Both had belonged to the rival Plaistow-based Chadd Green gang.

Lartey, of Abbey Road, Stratford and Virally Okokono, also 17, of Lonsdale Avenue, East Ham, were both members of the Maryland Bloods gang, who also had a fierce hatred for their Custom House rivals.

A fourth suspect, 16-year-old Chadd Green member Samuel Adelagun, who went by the street name Sammy Gunz, was shot dead in another gangland attack in October 2010 – three months after Ailton was murdered.

Lartey, Wilson-Moonie and Okokono denied murder but were unanimously convicted after a trial by an Old Bailey jury. Each was handed a life term and ordered to serve a minimum of 18 years.

Judge Timothy Pontius told them: ‘This was an attack upon a lone youth who had no chance – in the face of overwhelming odds – to defend himself and thus could do no more than try to run and then, on being caught, to protect himself as best he could.

The witnesses describe the pitiful attempts he made, in vain, to use a wheelie bin as a makeshift shield. He never stood a chance.’

Lartey, whose previous convictions include assault and affray, has a criminal record going back to 2007, when he was aged just 12.

He is already serving a 42-month jail term, imposed in October 2011, for a gangland robbery committed just three months after the murder.

Lartey and Okokono can be named for the first time after the judge lifted an order which had previously banned publication of their identities.

Ailton, the son of the Angolan police commissioner, moved to the UK with his mother, a doctor, in 1997 and had stayed behind with his grandmother and cousin in Custom House when she returned to her homeland.

The family moved to East Ham in 2005, but Ailton continued to associate with friends from Custom House.

Police believe he was not a gang member, but he was known to associate with those who were. Judge Pontius – who oversaw the trial of Stephen’s killers – said he was certain Ailton had not been involved in that murder.

His family say they now live in fear of reprisals because only three of his 20-odd attackers have been brought to justice. A 15-year-old witness, who gave crucial evidence during the trial, has also been moved away from the area by police because of similar concerns.

Wilson-Moonie was in the year above Ailton at St Bonaventure’s Roman Catholic School, Forest Gate, and both had tattoos reading: ‘Only God can judge me.’

But prosecutor Crispin Aylett QC said: ‘Once the school bell rang at the end of the day, whatever friendships might have been formed in the playground were put to one side in favour of what appeared to be tribal loyalties inspired by the postcodes of people’s addresses.’

Ailton was attacked in the early hours of July 4, 2010, as he cycled home from a party in Tant Avenue, Canning Town.

As he headed through down Boundary Lane, Upton Park, he was chased by a 20-strong mob – some of them on their own bicycles – into Denbigh Road, East Ham, where he was surrounded, dragged from his bike and beaten.

In desperation, he banged on the front door of a house, but the lone woman inside was too terrified to open the front door.

The gang called a temporary halt to the attack when they noticed another householder in her window on the phone to the police.

It allowed Ailton to stagger across the road, where he banged on the front door of another house. But his pleas again fell on deaf ears and the gang were free to carry on where they had left off.

One resident, scrap metal dealer Tony Gheorghiu, heard the gang striking their metal bars against a wall. ‘Then there was a big fight where everyone in the group was involved,” he said. “The entire group was screaming and yelling.’

After the attackers ran off, taking Ailton’s Specialized Hardrock mountain bike, another neighbour went to investigate and found Ailton slumped in a front garden. He had been stabbed 10 times and died in hospital two days later from a knife wound to his right lung.

But detectives were unable to charge anyone over the killing for 18 months after coming up against a wall of silence in the local community.

Detectives were eventually able to link Wilson-Moonie, Lartey and Okokono to the murder, after carrying out covert surveillance and scouring phone records and CCTV. Other suspected gang members have not been charged because of a lack of admissible evidence.

When Wilson-Moonie’s home was searched, police found a newspaper cutting of an article reporting the court case against his best friend’s murderer.

On the night Stephen was killed in 2009, he was arrested after he was found cowering in a car with other suspected gang members, wearing a stab-proof vest and brandishing a lock-knife.

Mr Aylett said: ‘Albeit that 18 months had gone by since the death of Stephen Lewis, nonetheless the murder of Ailton Campos De Oliveira was committed as an act of revenge. Ailton was murdered for his perceived link to the Custom House Gang.’

Wilson-Moonie, Lartey and Okokono, of Lonsdale Avenue, East Ham, all denied murder and conspiracy to cause grievous bodily harm with intent.

The conspiracy charge was left to lie on the file after guilty verdicts were returned on the murder charge.