Concerns have been raised about the number of children being excluded from primary school.
An analysis of official figures by the Labour Party has revealed a sharp increase in primary-age pupils being excluded.
Meanwhile, England's children's commissioner, Anne Longfield, has said that excluded primary children are vulnerable to exploitation by criminal gangs.
Need to know: Knife crime and schools
According to an analysis of Department for Education figures by Labour, the number of 5-10-year-olds in pupil referral units that are academies or free schools – where children excluded from mainstream education are taught – has more than doubled in just seven years.
They rose from 715 in 2011 to 1,572 in 2018, the party said, while the number of children placed in alternative provision paid for by local authorities was up from 2,475 to 3,714 over the same period.
The analysis also found that last year there were 42 under-fives in PRUs – of whom 28 were aged 2 or younger.
The Sunday Times reported yesterday that Ms Longfield will warn ministers at a knife-crime summit today that 30 children are being permanently excluded from primary schools every week of each term, with one in four being under the age of 7.
More than 1,200 under-11s were permanently excluded in 2016-17 – and just 1 per cent of primary schools in England were responsible for a third of those exclusions.
“The fact so many primary-age children are being excluded is shocking,” Ms Longfield said. “It used to be 11-13-year-olds who were on the edge of gangs. Now people are telling me that has fallen to 8-10-year-olds.”
Shadow education secretary Angela Rayner said the figures contained in Labour's analysis should be a cause for serious concern.
"It is deeply concerning to see such a vast increase in the number of very young children being taught in pupil referral units," she said.
"For too long, the Tories have sat by idly as some of the most vulnerable young people in our country are falling between the gaps and even out of education altogether."
Last month, London mayor Sadiq Khan and eight police and crime commissioners wrote to the prime minister to warn that the "broken" system of support for troubled and excluded youngsters lay behind the recent rise in knife crime.
They said excluded children were "sucked into criminality" and were "at much greater risk of becoming either perpetrators or victims of serious youth violence".
A DfE spokesperson said: "No matter the obstacles they may face or the backgrounds they're from, we want our young people to receive an education that fosters ambition and a confidence in their abilities.
"Pupil referral units exist to work with young people with more complex problems. The classes are often smaller, with more specialist teaching, and can offer the support and mentoring that vulnerable children need."