Eton College’s Head Master has said that he will not apologise for ensuring that staff and students “feel comfortable” but insisted that he does not want to “shut down debate”. Speaking out for the first time amid a free speech row that has engulfed the 580-year-old institution for the past week, Simon Henderson said that the school makes “no apology” for teaching pupils to respect each other’s differences. In a letter to parents, he said: “I went into teaching because I believe in the values of a liberal education and the importance of independent thinking and intellectual freedom. “Eton’s same belief in these values inspired me during my eight years as a teacher here from 2001 and were a key reason why I was so proud to return as Head Master in 2015.” Mr Henderson said these values are “non-negotiable” adding that he “believe[s] passionately that our pupils must learn to think for themselves rather than waiting to be told what to think”. But he added that both pupils and Masters should “feel comfortable being who they are and to treat each other’s differences with understanding, tolerance and mutual respect”. It is the first time that the Head Master has waded into the debate to defend his record on free speech. Last week a row broke out after The Telegraph revealed that a Master was dismissed for gross misconduct after recording a lecture which questioned "current radical feminist orthodoxy". The controversial lecture was part of the Perspectives course taken by older students to encourage them to think critically about subjects of public debate. Mr Knowland alleged that he was banned from delivering the lecture to pupils and then dismissed after he refused to remove a video of the lecture from his personal YouTube channel. Eton College has said that the dismissal was “not a matter of free speech” and instead one of “internal discipline”. An internal panel, chaired by the school’s vice-provost, will meet on Thursday to consider Mr Knowland’s appeal. In his letter to parents, Mr Henderson said he could not comment on the disciplinary process but added: “I trust and respect a disciplinary process where I was not a member of the initial disciplinary panel, which consisted of three of our most senior teachers.” He also thanked parents, pupils and staff for sending him “letters of support” during the week. Yesterday the Education Secretary said that Eton College should admit girls, adding that this would be a “good step forward”. Gavin Williamson said he would be “very much in favour” of the £42,500-a-year Berkshire boarding school admitting female students, after being asked whether this would “sort out their problems”. Pupils have launched a petition calling on the Head Master to reinstate Mr Knowland, and accusing the school of "institutional bullying". Earlier this week, an Eton College Master broke ranks to attack the school’s “indoctrination” of students. Dr Luke Martin, who teaches Divinity at the school, recently stood down from his role as the Master in Charge of Perspectives. In a letter to the school's vice-provost, he said he is beginning to “lose faith” in Eton’s ability to promote independent thinking among its pupils. A spokesman for Eton College said the school has no plans to admit girls and that the vice-provost is chairing Mr Knowland’s appeal panel so cannot comment on the contents of Dr Martin's letter.