Children as young as five were suspected of hundreds of crimes including rape, arson and assault last year.
Figures released under the Freedom of Information Act reveal West Yorkshire Police recorded nearly 400 alleged offences linked to children under the age of ten during 2015.
They included a combined total of 37 cases of sexual assault or rape against boys or girls under 13, and one where the suspect was just four-years-old.
However, the alleged child offenders cannot be prosecuted for the crimes because of their young age.
A total of 87 children were suspected of assault, some causing injury, while 24 thefts and nine cases of arson were recorded by the force last year.
The age of criminal responsibility in the UK is ten, which means children under ten who are alleged to have committed a crime cannot be held responsible for wrongdoing.
The youngest suspect linked to an offence in 2015 was just three-years-old.
A five-year old was suspected of raping a girl under 13, while two four-year-olds were alleged to have sexually assaulted a boy under 13, the figures also reveal.
Detective Superintendent Darren Minton, of West Yorkshire Police’s Safeguarding Central Governance Unit, said the force works with children and parents to address causes and motivations for offending.
He said: “While a suspect under the age of 10 is under the age of criminal responsibility and therefore will not be subject to the criminal justice process, alongside partner agencies, we will work with them and their parents to address the causes and motivations of their offending.
“Details of children who have committed offences are shared with the relevant local authority to provide further support as necessary via their Multi-Agency Safeguarding Hubs.”
Other alleged offences last year include four children under ten found in possession of an article with a blade or point, and 76 cases of criminal damage.
There were 378 offences linked to suspects under ten last year, more than double the 135 recorded by the force in 2014.
The 2014 figure was double the previous year’s 71 alleged offences in 2013.
But, Det Supt Minton said changes in the way crimes are recorded was behind the increase and that the force had not seen a “marked” rise in actual offences.
He added: “To put these figures in context, offences involving suspects under 10-years-old make up an extremely small percentage of overall crime.
“As part of our victim-centred approach, we record all crimes - even where the suspect is immediately identified as a child under the age of 10.
“Previously, these offences would either be no-crimed or marked as ‘undetected’ but since June 2014, in accordance with revised Home Office guidelines, we now finalise such offences as ‘outcome 11’ - prosecution prevented, suspect too young.
“This has resulted in an increase in recorded crimes with suspects under 10-years-old but I would stress that we have not seen any marked increase in actual offences in this time.”
There were 17 alleged offences linked to suspects under ten of sexual assault on girls under 13, and nine on boys last year.
And there were nine linked to offences of rape on girls under 13, and two on boys.
In April 2014, the government introduced new, more detailed way of recording crimes. Outcome 11, one of the new crime outcomes, was adopted by West Yorkshire Police in June 2014.
Offences which were recorded before Outcome 11 came into force but fit the its criteria were previously recorded as “Undetected”.
‘How mature is the child?’
A child under ten who is alleged to have committed a crime cannot be prosecuted under current legislation.
That’s because they are deemed to be under the age of criminal responsibility, and therefore cannot be held criminally responsible for wrongdoing.
Phillip Goldberg, managing partner at Lester Morrill Solicitors in Leeds, said the real question is the maturity of the child involved.
He said: “Whilst there are numerous offences committed by children under the age of 10, historically it has always been felt by the criminal justice system that at that age a person cannot be criminally responsible for their actions.
“However strictly speaking when children offend there is no specific age whereby they should be dealt with by the courts but 10 is usually the youngest.
“The actual question is how mature is the child as an eight-year-old? They may be more mature than a 12-year-old and have more ability, and so understand the difference between right and wrong and the consequences of their actions.”
Children under ten who do offend can be taken into care by the local authority.
Mr Goldberg said placing them in care is often a better alternative to criminalising the child.
He said: “For those under the age of 10 if they are committing serious violent or sexual offences then the Criminal Justice System is not the appropriate venue to resolve the issues they have.
“Social Services do have the skills required and can take action to ensure the child not only receives the help they need but also can, if the circumstances require, take the child from the environment they are in for their own welfare , and the welfare of other children, and place them in care.
“Whilst this may seem drastic if the child has committed a sexual offence then it may be necessary to protect others.
“By taking this action the child hopefully will mature and with specialist help prevent them from committing further offences in the future whilst at the same time the child will not be criminalised.”