Amanda Spielman said she was “concerned” about a kind of activism which she said “demands immediate adherence to a position”.
England’s chief schools inspector made the comments during a speech to the Festival of Education, in which she said a phenomenon taking place is a “confrontational brand of activism” which is “problematic for schools”.
“Activists have shaped society and play a major role in changing the world for the better – most obviously in promoting civil rights and pushing for the kinds of legislation that dramatically improves the lives of whole sections of society,” she said.
Ms Spielman also praised the Everyone’s Invited campaign, which saw thousands of young people share testimonies of sexual abuse.
“What I’m concerned about is not the activism that broadens debate and brings about long-term change but the militant kind of activism that demands immediate adherence to a position,” the head of Ofsted said.
“We are seeing these confrontational approaches both outside and inside schools. It’s affecting staff, parents and children and can have a limiting effect on education.”
“Let’s not have teachers policed by self-appointed ‘moral guardians’ who refuse to tolerate an alternative viewpoint. Or harried on social media into apologising for what they’ve said, or into changing the way they teach, in the face of militant activism.
Addressing sector leaders on Thursday, Ms Spielman said: “It cannot be right for children to have to cross what amount to picket lines outside their school because one group’s religious beliefs - protected by law - sit uncomfortably with teaching about another group’s sexuality - also protected by law.
“It cannot be right that the curriculum can be filleted by pressure groups.”
Protests have taken place outside school gates in recent years, including parent demonstrations at some primary schools in Birmingham in 2019 against children being taught about LGBT+ relationships.
More recently, protests were held outside Batley Grammar School in March after a teacher showed Year 9 pupils a caricature of the Prophet Mohammed during a lesson.
Ms Spielman said there has been a rise in activism led by pupils.
It comes after a high-profile campaign from students at Pimlico Academy in London who claimed uniform policies were discriminatory.
Ms Spielman added: “Some of this is about racism, or anti-racism; some is about climate change; some is about issues that are quite remote for most British children, such as the charged and complicated politics of the Middle East.
“But in some cases children and teachers are suffering abuse or even violence, simply for being who they are: for being the wrong religion, or race, or ethnicity. This is completely unacceptable.”
Ms Spielman addressed the Festival of Education the day after Sir Kevan Collins, the ex-education recovery tsar who stepped down amid a row on catch-up funding, spoke during an event, saying he did not believe the impact of the Covid pandemic on children’s wellbeing was yet known.
Additional reporting by Press Association