Teachers' unions had earlier been concerned about racism against Polish children and other European immigrants. Last year, 11,000 of them took up places at schools in England.
The Polish Educational Society in London, an umbrella organisation that co-ordinates teaching activities for Poles abroad, said it had received many complaints and requests for help from heads about racism by Polish pupils in the classroom and playground. Such instances included telling fellow pupils that white people were better than blacks, terrorising black pupils and moving their desks away from Pakistani and Indian children.
Heads have also reported instances in which Polish parents have asked schools whether their children were going to be taught by "darkies". Pupils had also learnt abusive words from their families.
Malgorzata Masznic, head of the society's office in London, said:
"Recently, a school head in Acton approached us regarding 16 Polish teenagers who hurl racist insults at black teachers and pupils on a daily basis. Their behaviour has brought the entire school to a functional standstill."
One head complained about Polish pupils who drew apes sitting in palm trees on the classroom whiteboard, and then explained that it was what their black classmates and teachers looked like.
Ms Masznic said schools wanted help from them and other Polish organisations to deal with the children's parents, who sometimes could not speak English.
"But these are not one-off situations," she said. "The scale of the problem is just too vast. We can't make appointments with several hundred people a month."
Psychologists said racism was rooted in Poland's virtually all-white culture. Janusz Czaplinski, a social psychologist at Warsaw university, said: "When Polish children arrive in multicultural Britain, the shock sets off a psychological mechanism of rejection of everything that's different."
Kryztyna Milewski, an adviser at the Polish embassy in London, said: "These children have mostly been taken away from small Polish towns... Often, they can't speak English. All that can't just happen without some kind of tension."
But the problem is by no means universal. Several heads with high numbers of Polish pupils told The TES they had never experienced such problems.
David Braham, head of Bengeworth first school in Worcestershire, said:
"Their attitudes are brilliant. They learn English quickly and work incredibly well. We've never experienced any prejudice or racism."