Austerity-driven cuts that have left disadvantaged children vulnerable to gangs must be reversed to repair Britain’s “social fabric” and reduce crime, a police chief has said.

In a damning indictment of the effects of years of austerity on crime, Jon Boutcher, the chief constable of Bedfordshire, called for police to be freed up to focus on hardcore criminals and not victims of social “circumstance”.

In an interview with the Guardian, the former national police lead for race said that no number of extra police officers would make the streets safer if the heavy impact of the cuts continued to weigh on officers across the UK.

Last week Boris Johnson took office as prime minister and announced plans to hire 20,000 officers, in effect reversing cuts made to frontline law enforcement since 2010, when the Tories came to power.

But in an interview to mark his retirement, Boutcher said: “Twenty thousand more police officers is essential, but to allow those police officers to do the job the public want, don’t distract us by us having to repair and look after those that are not adequately supported because of the lack of investment in their public services, particularly mental health provision. We need to repair the social fabric.”

He said the “conveyor belt” of the criminal justice system was not working and significant numbers of offenders could be diverted from crime with a bigger investment in social services, education and mental health. Picking up demand from the crumbling mental health system was a big issue for policing, he said, and from the education sector, with schools excluding children who end up on the streets.

“The first responsibility of government is to protect its citizens. That comes about in a number of ways. Policing is a core part of that, but other public services have to be properly funded to ensure we all feel safe,” he told the Guardian.

Jon Boutcher spoke to the Guardian in an interview to mark his retirement. Photograph: Brian Lawless/PA

Boutcher’s force covers Luton, where he said swingeing cuts had left children vulnerable to exploitation.

“There has been a 50% cut in the funding of youth services in Luton as the council could not afford it. You take those services away, kids go in the parks and hang around the streets and are vulnerable to gangs and others who will exploit them, as a consequence of failing to properly fund those services.”

He added: “Twenty thousand [more officers] is the recovery of what we lost since 2010, but we also lost 20,000 police staff who do key jobs. We’ve also seen an increase in demand, and 999 calls have gone through the roof.”

Boutcher is a former a senior Scotland Yard counter-terrorism detective, who led the hunt for the men who attempted to bomb London on 21 July 2005.

His public comments echo private sentiments among some police chiefs that a significant proportion of crime is linked to social conditions.

“There are so many areas where we could improve the life chances of people, rather than arresting them and putting them into a conveyor belt of the criminal justice system, which often leads to them becoming harder and harsher criminals,” Boutcher said.

“Our prison service – again underfunded – does not provide the rehabilitation and support for those offenders to change their ways. Policing is a blunt instrument. For some, a hard response from policing is what is needed. We are failing too many people who, given the opportunity and choice, would not go into crime.

“There are a significant number of people who are lost in our society and create a demand for today’s policing. That is due to other services not providing for their mental health, wellbeing or life chances.”

Boutcher added: “I’m not a liberal-hearted, lefty softy. But let us police those who want to damage our society and choose to damage our society. But provide the support for those who are caught by circumstance and give them pathways away from crime. That needs more money. Let us concentrate on those who choose to be criminals.”

He also said thousands of the new officers promised by Johnson would be stripped from the frontline because of a new “academic” training regime for recruits that he and other chiefs opposed. Instead of 16 weeks’ training, they will study a three-year course involving significant periods of time off the frontline.

Q&A How many police officers are there in the UK? Show In March 2019 there were 126,000 police officers in England and Wales. This includes 4,000 officers from the British Transport Police. Policing is devolved in Scotland, and the country has had the equivalent of between 16,500 and 17,000 full- time officers for the best part of a decade. Northern Ireland has around 6,500 officers. Police officer numbers in England and Wales have declined by 20,000 since 2010, when the Conservative and Liberal Democrat coalition came to power. The number of police officers in England and Wales is at its lowest recorded level since the Margaret Thatcher administration in the early 1980s. Boris Johnson has pledged to recruit 20,000 new police officers.

“The PM wants his 20,000 cops to keep people safe and protect communities. He does not want them in the classroom,” he said, adding: “Have I used a protractor in the police? No.”

Boutcher levelled strong criticism at the service for its record since it vowed to radically change after the 1999 Macpherson report found it was institutionally racist.

He said: “Some chiefs get it; too many do not because it is not a priority for them and their force. Race rises and falls on the agenda of policing and society.”

Just 6.6% of officers are from a minority ethnic background, compared with 14% of the population as a whole. The Metropolitan police, which covers London, estimates at the current rate of progress it will take another 100 years to reflect in its makeup the communities it serves.

Boutcher said low minority ethnic recruitment was a result of continuing problems within policing deterring people from joining.

“They do perceive we are racist. They do not see policing as an organisation they can join. People’s perceptions are often their reality. It’s not good enough saying we are not racist – we have to demonstrate it.”