Almost half of all secondary school headteachers have contacted the police for advice on combating violent extremism, according to new Government-commissioned research.
A quarter of primary heads have asked officers for help, with this figure rising to one in three among those working in London, according to the Ipsos Mori survey of 804 schools.
Department for Education (DfE) officials ordered the study to find out if schools are obeying the new duty to promote community cohesion. Researchers were also asked to find out how many schools were engaged in the Home Office's counter-terrorism strategy, Prevent.
According to the study, the police are not the only port of call. Three-quarters of headteachers overall have requested some kind of help to prevent violent extremism among their pupils.
Other widely used sources of information are DfE guidance (48 per cent of schools), local authority guidance (32 per cent) and the media (30 per cent).
Heads in richer areas, and those whose pupils come from less multicultural backgrounds, were less likely to have asked for guidance on how to prevent violent extremism.
"It may be that a more detailed understanding of their role in preventing violent extremism is driving secondary schools to seek information and support for their work," the report says.
"They may also have a more developed sense of the types of support they should be seeking and, in turn, where they might source it."
Joan McVittie, head of Woodside High School in north London and vice-president of the Association of School and College Leaders, said: "Heads are asking for information because they want to know what to look out for, and they know they should be alert to potential problems.
"When I took over the running of this school there was conflict between Turkish and Somalian pupils and we did a huge amount of work to stop this. Now, whatever prejudices pupils have, they dump them at the school gate and we have a good school community."
The aim of Prevent, which is being reviewed by the coalition Government, is to stop people from becoming or supporting terrorists. Heads have been asked by the Government to identify issues, run training for teachers and "engage" the community in their work.
A total of 84 per cent of school leaders said they knew "at least something" about their role in preventing violent extremism, but 20 per cent said they regarded this work as "unimportant".
Building resistance and resilience
Staff in half of the 804 schools which took part in the survey, called Community Cohesion and Prevent: how have schools responded?, said they used the curriculum to "build resistance" to violent extremism. In addition, 94 per cent of schools used the curriculum to promote community cohesion.
Three-quarters of teachers said they built pupils' "resilience to violent extremism" through the "ethos and values" of the school, 67 per cent through internet safety policies and 67 per cent through PSHE lessons.
A third of primary and secondary schools do not have a teacher with responsibility for preventing violent extremism. But the researchers found that only 5 per cent of schools do not have a teacher responsible for improving community cohesion.