Head teachers have warned that intimidation is still continuing after the investigations into the so-called Trojan Horse scandal.
A head teachers' conference has heard claims of threats such as dead animals being left in school playgrounds.
"Trojan Horse has not gone away," said Sarah Hewitt-Clarkson, head of Anderton Park School in Birmingham.
Responding to the claims, Education Secretary Nicky Morgan, pictured, said: "There is no place for extremism in our schools."
The National Association of Head Teachers' annual conference in Liverpool heard warnings that problems over extremism remained unresolved and schools could still face pressure on issues such as tackling homophobia.
The so-called Trojan Horse inquiries followed allegations that there were organised attempts by hardline Muslim groups to undermine head teachers and take over schools in Birmingham.
Head teachers at the conference complained that no governors had been barred as a result of the inquiries and they called for a database which would identify individuals removed from governing bodies.
Ms Hewitt-Clarkson told the head teachers' conference: "Trojan Horse has not gone away. Those of us who were involved, we knew it was the tip of the iceberg. We still have dead animals hung on the gates of schools, dismembered cats on playgrounds. We have petitions outside schools, objecting to teachers teaching against homophobia."
