A head teacher at a primary school giving lessons on LGBT equality has received threatening emails and phone calls.
Police are investigating messages sent to Sarah Hewitt-Clarkson at Anderton Park Primary School in Birmingham.
There have been seven weeks of protests outside the site from which “hundreds” of pupils were kept away on Monday.
Birmingham MP Jess Phillips has called for an exclusion zone at the school to limit where people can demonstrate.
Ms Hewitt-Clarkson has branded the protests aggressive.
The city council is looking into Ms Phillips’ request, with the authority’s leader saying some outside the school are “peddling hatred”.