A scheme aiming to turn children arrested for violence away from crime has claimed staggering success, with up to nine out of 10 diverted from further offending, according to a report.

Under the scheme, which is funded by London’s Violence Reduction Unit (VRU), special youth workers are placed in police custody centres across the capital.

The VRU claims the overwhelming majority of 10- to 17-year-olds do not reoffend within 12 months of release from custody after intervention.

Lib Peck, the director of the London VRU, said the £40m-a-year cost of the unit, which runs a range of initiatives, was more than made up for by the money saved from the cost of reoffending.

She said prevention worked and deserved more money, adding: “Society and government have focused a lot more on policing and enforcement than they have on prevention.”

A report to mark London VRU’s first five years of operating says the cost of youth violence in London alone is £1bn a year, including the cost to the police, courts system, health and victim services.

VRUs sprung up across the UK amid a growing concern over knife crime. London’s unit is the biggest, with the capital also suffering the highest rate of knife crime.

The scheme includes support based at hospital emergency departments aimed to stop retaliation from victims of violence, as well as services in police custody suites that have tried to help 800 children.

The report details what drives violent crime and how a public health approach can help reduce it.

It says: “Monitoring data shows that nearly three-quarters of young people in hospital following a stabbing or violent incident reduced their risk of harm after the intervention from a youth worker.

“And last year, data reported by our projects showed that almost 90% of teenagers arrested for violent offences did not reoffend over the next 12 months following intervention and help from a youth worker based in the busiest police stations in London.”

The scheme is showing signs of being able to exploit the “teachable moment” long talked about by police and youth workers. It is the point where someone is wavering between continuing as a criminal or turning their back on violence.

Michael Gosling, one of the London youth workers based in police custody, said he tried to earn childrens’ trust and told them not to discuss their crimes with him, with most wanting to talk about what had led to them being under arrest.

“Going into custody can be quite scary,” he said. “I try to appeal to them by using body language. I tell them I am there for them, I am not there to judge them. We are not wearing the get-up of a police officer. I make it clear I am not a police officer.”

VRUs, and the expansion of youth work they involve, represent an attempt to counter attitudes supporting violence. Gosling said of one case: “He was a product of his environment.”

Some youngsters were driven by needing money to eat, others by buying trainers or just exploiting “the playground of opportunities”, Gosling said. “Older gang members are looking for younger children who are vulnerable, to recruit them,” he added.

Gosling said others saw violence as a necessary part of their attempt to make money: “The thought process is: here and now. They are out to get it by any means necessary.”

The report says low trust in the Metropolitan police damages the fight against crime: “Trust and confidence in policing have seen sustained declines over recent years – just 46 percent of Londoners believe the police do a good job in their local area. This is 10 percent below where it was 5 years ago.”

One young person mentioned reportedly described their reluctance to report a crime to the police, “saying they weren’t sure if they would be treated as a victim or perpetrator. They described feeling ‘powerless’”.

Peck said: “I don’t think you can get away from the fact that it’s a very problematic relationship at times. We just see the consequences of it.”

The VRU also claims success reducing school exclusions, and says children not in education are more likely to become involved in violence. Peck said: “Whatever the cost to the taxpayer [of the VRU] we are saving the same or saving more.”

Since the VRU started in 2019, homicide rates are down in the capital. Its murder rate is now lower than Paris, Toronto, Manchester and Berlin, but higher than Rome and the West Midlands.

Other crime types are increasing, however, and London’s VRU, largely funded by the mayor, is seen as a long-term project for a decade or more.

Key factors driving violence remain poverty, deprivation and alienation, with drugs a key factor – 56% of homicides between 2012-13 and 2017-18 in London were drug-related, according to the report.

There has also been an increase in the proportion of 10- to 14-year-olds suspected of violence.