Children below the age of 12 have been caught carrying knives at Suffolk primary schools in a year that knife crime reached a record high for the county, it can be revealed.

Suffolk Constabulary were called to 20 cases in which children were found to have knifes at primary or secondary schools or pupil referral units in the last academic year, 2016/17, police figures shows.

This was an increase from just four in 2015/16 and has followed a number of stabbing incidents and other high-profile serious crime, particularly in Ipswich, which saw knife crime rise to a five-year high in Suffolk and Essex.

Ipswich’s area commander, Superintendent Kerry Cutler, backed by campaigners, expressed alarm and called on both parents and school leaders to help address the problem, but suggested the rise in the figures may be the result of increased confidence in reporting rather than an increase in incidents.

Schools in the Ipswich area were the worst affected, the freedom of information data found. The majority of all cases were dealt with by youth cautions.

Authorised headteachers and staff can search pupils or their possessions without consent if they suspect there could prohibited items such as knives.

Anti-knife crime campaigner Caroline Shearer, whose son Jay Whiston died after being stabbed at a house party in Colchester in 2012, said she suspected some headteachers were being “ostriches with their heads in the sand” and not reporting incidents for fear of developing a negative reputation.

“It is becoming more and more common and the kids are getting younger and younger – as young as eight and its tumbling down,” said Mrs Shearer, who holds anti-knife crime workshops in Essex schools and hopes to bring her work to Suffolk next year.

“It’s scary. We ask them why and they don’t know. But they all got their knives from the kitchen...I’m fed up with excuses like they come from poor backgrounds.

“The kids are learning it from somewhere; from their peers, or what they’re allowed to watch on television. Parents need to retake control.”

She also called on schools to make greater use of metal detector wands on school premises.

Ms Cutler added: “It is a concern but it needs to be put into context; it’s not hundreds.

“A lot of the time it is due to a fear of crime, for self-protection, or for status to look big. But knives are more likely to be used against them.

“Schools and parents need to engage more and spot the signs.”

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Exam results pressure and a narrow curriculum restricts how teachers help students caught up in knife crime, according to Graham White, National Education Union member for Suffolk.

He added: “I’m sure many would like to do more (to tackle knife crime), but it doesn’t get the time it deserves.”

London mayor Sadiq Khan believes Ofsted should judge schools on how effectively they are rooting out knife crime. He said he wanted Ofsted to include in its school safeguarding standards whether pupils were being kept safe from blades and deterred from carrying them.

Ofsted is set to carry out a thematic review of tackling violence at schools, including best advice on prevention.

Mr White added: “Society is becoming ever more competitive and so it is possible that some young people feel they cannot compete. Society has failed them in some way and so knifes are a way of increasing their perceived value and importance.”