More than 100 children in Kent, some as young as seven, have been caught with weapons in classrooms but are too young to be prosecuted.
Figures from Kent Police revealed that 109 children were investigated for possessing, or threatening with, an offensive weapon or blade between April 2017 and December 2019.
Two children, aged seven and nine, were not prosecuted because of their age.
The authorities have little power to act as the age of criminal responsibility in England and Wales is 10 years old.
Anyone under the age of ten cannot be arrested or charged with a crime.
The data, obtained under the Freedom of Information Act by the Press Association, also showed that a ten-year-old was let off for the same reason - as they were suspected of committing an offence while below the age of criminal responsibility.
The most common age for suspects was 14, accounting for 23 incidents.
Five adults, aged 45, 35, 31, 19 and 18, were also investigated for having knives at school.
Superintendent Mick Gardner, from Kent Police’s Tactical Operations Command, said: "Kent Police takes tackling knife crime seriously and is committed to removing weapons from communities and addressing the culture around carrying bladed items.
"The force has dedicated youth engagement officers who carry out vital work in schools and colleges, helping to educate young people about the dangers of violent crime.
"Any incident involving a young person and a knife is one too many for Kent Police, but it is important to note that the figures showing 109 children reported for being in possession of a weapon relate to possession, and not assaults.
"We will continue to work with schools and other partner agencies, as well as parents and guardians, to safeguard children and help them make better life choices."