Parents and former pupils at Eton have spoken out in support of its headmaster who sacked a teacher after he posted a provocative lecture on YouTube attacking “radical feminist orthodoxy.”

Headteacher Simon Henderson was criticised for firing English teacher Will Knowland over the video, which Eton provost Lord Waldegrave claims Knowland refused to remove.

The video, designed as part of the school's “perspectives” lessons and intended to provoke the boys into debate, challenges the idea that most differences between men and women are not based on biology. It was never actually used in lessons after Mr Knowland was asked to remove it from the school's intranet.

Mr Henderson has been publicly criticised for his modern approach to social issues, addressing questions such as the gender pay gap and Black Lives Matter. Some students believe the sacking was an attempt to stifle "free speech".

But Fabian Pountney, a former pupil, told The Times: “There was always a lot of resistance from certain groups of boys, and I think that extended to some of the teachers as well.

“The fact that there are teachers at the school who criticise and have criticised [Mr Henderson] and there are boys at the school criticising him now is evidence there is not an orthodoxy of ideas.”

Matt Darby, an Old Etonian whose son is in his second year at the school, added: “I’m not really aware of any oppressive culture at the school,

“I would expect the school to engage in new social norms as they change. These don’t strike me as being oppressive or particularly out of the mainstream.

“I would expect children at Eton to be given a really well-rounded education that takes account of what’s happening in the world around them. I think there is just a touchpaper waiting to be lit among lots of people who are very nervous about change in the world.”

Ben Hammond, who has one son currently at the school, said: “Everyone who is a current parent had the opportunity to do full due diligence on Simon Henderson, who has been unfailingly open and honest about his belief in the need to educate boys in emotional intelligence, alongside academics.

“That’s exactly what we signed up for. There is no Trojan horse here. Anyone who is pretending to be surprised today at Mr Henderson’s ‘agenda’ may have some political motive, or is simply ill informed.”

Mr Knowland is expected to appeal his dismissal tomorrow (December 8).