Police chiefs have defended a 43% year-on-year rise in the number of officers based in UK schools.
The Runnymede Trust race equality think tank found 979 Safer Schools Officers (SSOs) in schools last spring, compared with 683 in 2021.
It found SSOs are more likely to be based in schools with higher numbers of children on free school meals, often with higher numbers of black pupils.
But the National Police Chiefs' Council says SSOs play an essential role.
The Runnymede Trust gathered the Freedom of Information data following the case of Child Q, a 15-year-old black girl who was strip-searched by the Metropolitan Police at school without an appropriate adult present.