Extremists have tried to intimidate Britain’s schools watchdog over its crackdown on unregistered Muslim schools, where inspectors were called “Britain First paedophiles”.

Ofsted boss Amanda Spielman revealed that inspectors at one of the regulator’s regional offices have been forced to take additional security measures after they were were repeatedly sent radical Islamic literature.

The chief inspector of schools accused a “mixture of Islamic extremists and the hard left” of using threats and intimidation to halt Ofsted’s attempts to crack down on hardline elements of Islam in schools in England and Wales.

“I had an email, which was the most threatening one, which was along the lines of ‘We know where you live and we can get you any time we want to’.”

Spielman disclosed that, after a court ruled that segregating boys from girls at a Muslim school was unlawful sex discrimination, her home address had to be wiped from the internet following an email which said: “We know where you live and we can get you any time we want to”.

“I’m not easily bruised. I don’t fall over when I see a load of nasty tweets pointed at me, but there has been some pretty venomous stuff,” she told the Times on Saturday in an interview.

Tackling illegal faith schools has proven to be the most difficult part of heading Ofsted since she took the role on earlier this year, Spielman said, telling the newspaper some of the abuse and threats that staff have been faced with while trying to carry out this task.

Inspectors visiting an unregistered Islamic school in east London were “so shocked” by the aggressive behaviour of staff — who called them “Britain First paedophiles” and accused them of committing sex acts to get their jobs — they reported them to police for breach of the peace.

And during a visit to a Muslim independent school, Spielman recalled, the head teacher phoned parents to tell them inspectors were asking their children if they were gay. Telling the Ofsted staff that angry parents were lining up outside the school, he asked inspectors whether they really wanted to proceed.

Breitbart London reported last month how Ofsted was so concerned by literature found by staff during inspections of Muslim schools that the regulator compiled a dossier of the worst examples.

Among the material were books encouraging domestic violence, marital rape, and Islamic supremacism, while it was found that sexist homework assignments were being marked approvingly.