More than 400 children under 10 were suspected of violent offences across Yorkshire last year but could not be prosecuted because they were under the age of criminal responsibility.
Crimes by under-10s in the past four years also included rapes, drugs offences, robberies, burglaries and arsons, police data obtained through the Freedom of Information Act shows.
Now, with crimes by those aged 10 to 17 also on the rise, police commissioners have said “huge reductions in youth services” are contributing to the problem.
Mark Burns-Williamson, West Yorkshire’s Police and Crime Commissioner, described the picture as a “worrying trend”.
He said: “There is no question that youth crime generally, pre- and post-10 years old, has been exacerbated by the significant cuts to public services across the board, both locally and nationally, as tackling the related issues are quite complex and often includes a host of partner agencies. Police involvement with children under 10 years old is a last resort but becoming more necessary due to the gaps in other services.”
Fellow Labour police commissioner, South Yorkshire’s Alan Billings, said youth clubs and activities in his area were “just disappearing”, not just in urban centres but in former pit villages too.
He said: “It is absolutely true. Local authorities have withdrawn from a lot of youth provision, not because they want to but because they have had to do it.”
He said his office gave out grants to help fund youth clubs where they could.
Police forces also said they were now better at recording crime, meaning the full extent of offences by children was now being revealed for the first time.
Detective Chief Superintendent Lisa Atkinson, Head of Crime at Humberside Police, said: “More incidents are now recorded as crimes which gives us a more accurate picture of what’s happening in our area.
“This helps us and our partners - such as social services and local authorities – give the right and best support to vulnerable people.”
Detective Superintendent Jon Morgan, of West Yorkshire Police’s Safeguarding Central Governance Unit, said since June 2014 his force had recorded all crimes where the suspect is identified as a child under 10, whereas "previously, these offences would either be no-crimed or marked as ‘undetected’".
A Government spokesperson said: “Violent crime has devastating consequences on our communities, and our serious violence strategy signals a step change in the Government’s approach by working with a range of agencies to focus on early intervention alongside strong law enforcement.
“The strategy puts a stronger focus on steering young people away from violence, helping them to change their behaviour and actions before they reach the stage where they are at risk of entering the criminal justice system.”
Children as young as two were among those suspected of crimes across Yorkshire in the past four years, it can be revealed.
In West Yorkshire, police dealt with 1,660 crimes involving suspects under 10 from 2014 to 2017 figures show.
This included a two-year-old and a six-year-old jointly suspected of a sexual offence in Leeds in 2016 and a two-year-old and an eight-year-old jointly suspected of a sexual offence in Bradford in 2015.
Over the same period in South Yorkshire, officers dealt with 483 crimes involving suspects under 10, including 25 allegations of rape of a child.
A two-year-old was suspected of sexual assault on a female child, a nine-year-old was suspected of possessing a firearm and two eight-year-olds were suspected of possessing cannabis, information released by South Yorkshire Police shows.
In the Humberside Police force area, there were 371 crimes where the suspects were aged under 10, the youngest aged two.
Crimes by suspects aged nine or under included rape of a female child, arson endangering life, burglary, knife possession and robbery.
In North Yorkshire, there were just 10 children aged nine or under suspected of crimes over the four-year-period, data released by its police force showed.
Suspects included a five-year-old girl and a five-year-old boy.
The crimes included violence and sexual offences.
Across Yorkshire, there were a total of 2,446 crimes where the suspects were under the age of criminal responsibility.
Two-fifths of them (42 per cent) were violent crimes.
Violent crimes by under-10s rose six-fold from 64 across the region in 2014 to 425 last year, the figures showed.