An underworld war has raged in Liverpool over the past decade, fought for control of the city’s lucrative drugs trade.

At the heart of this war is a continuing battle between rival gangs that have overrun Croxteth and Norris Green, two Liverpool council estates that are separated by a dual carriageway, and the scene of Rhys Jones’s murder.

The gangs here defend their territory fiercely and operate under a warped code of honour by which cross-boundary intrusion is interpreted as an act of war. If one criminal encroaches on another’s territory, revenge is swift and it doesn’t always matter who is punished.

The mentality and modus operandi of the gangs who run these areas were outlined to The Times yesterday by two former criminals with extensive knowledge of Liverpool’s crime gangs.

Bob Croxton and Brian Dean have both served time in prison for drug dealing and violent crime respectively. Mr Croxton now runs an organisation that seeks to rehabilitate ex-offenders. Mr Dean, who served in the Army for 13 years, is the group’s arms expert. Shaven-headed and hard as teak, they are the sort of men, on first encounter, that you wouldn’t mess with.

While they have no knowledge of any of the details of Rhys’s murder, they explained that it was essential to understand the way in which the gangs operate here to gain any insight into the possible reasons behind Rhys’s death.

The gangs deal in drugs, the biggest currency of Liverpool’s underworld. But while the gang leaders run the business, they leave it to those at the bottom, the children – many aged as young as 11 – to do their dirty work. And that includes acting as hitmen or, in gang terminology, “postmen”.

The children are recruited first as low-level dealers, and gradually promoted to more senior roles.

They are easily recruited, drawn as they are to the “glamour” of the drugs gangster and the easy money to be made working for them.

For their part, the dealers employ young children to do their work for them for the simple reason that they are less easy to detect, according to Paul Breen, an ex-gang member who has written a book about his experiences.

“People don’t pay much attention to a 13-year-old on his BMX,” he said. “You’ll have a kid on a push bike who does deals on wheels.

“The addict dials the number of a phone box where the kids have been told to hang around. The kid will set off on his push bike.

“If the grown-ups make a delivery, they will take three kids with them in the car. If the police stop the vehicle, the kids’ job is to swallow what they have.” Once they’ve proved themselves in junior roles, the children take on more serious jobs, including violence.

“The guys at the top, they’re never going to get their hands dirty and risk being caught with a pistol,” said Mr Croxton.

“It’s the younger kids, lower down the line, who end up carrying out their masters’ orders.”

In the world of the young teenage wannabe, fuelled by hardcore rap music and the Hollywood myth of gangster as antihero, the gun has become the ultimate status symbol, an iconic designer accessory. Mr Dean poured scorn on the suggestion that guns in Liverpool are readily available on the street for as little as £50.

“For £50? All that will buy you is a worn-out heap of junk that’s for sale because no one else wants to use it,” he said.

“You’re looking at £750 to £1,000 for a converted replica pistol that won’t blow up in your hand, and even more for a real pistol.”

Children such as Rhys’s killer could never afford to buy such a weapon.

“The young kids look at the older ones. They’re desperate for a taste of that glamour and excitement, desperate to prove that they belong. If someone’s got the balls to be a shooter, they go up the ladder.”

When a child is sent off on a hit, he receives the pistol only hours before he sets off, and hands it back after his mission. It will be loaded with bullets bought for £2 each from an affiliate of the gang who will have manufactured them himself, probably in his garage, said Mr Croxton.

Within hours of the shooting, all evidence that could identify the attacker is destroyed.

“The pistol is handed on, possibly to someone who is being paid to keep it. Not long after that, every article of clothing the youth was wearing is burnt and his BMX bike crushed.”

Both men denied that they were attributing too much organisational sophistication to the city’s drugs gangs.

“These people don’t mess about. When one notorious gangster died in Norris Green, they ordered the local shops to close on the day of his funeral. No one disobeyed.

“You’ve got to remember that Liverpool is one of the biggest sea ports in the country. Drugs are big business here. London gets a lot of its drugs from Merseyside. A gram of coke costs £60 in the capital. It’s only £40 here.”

As for the children involved, they are already lost to the drugs underworld.

“We’ve got to stop thinking about some of these young gang members as children,” said Mr Breen. “They are committing adult crimes and they are thinking like criminals.

“And forget all this stuff about cowardly crimes. They are Liverpool kids. It isn’t in them to be cowards. They’ve got nothing, so they’ve got nothing to lose.”

Times Recommends

• Margot Fonteyn: In her footsteps
• Forget beautiful people, let's have wonky Brits
• Fundamentalist brew: faith and power