A teacher at one of the top independent schools in London has reportedly told a Jewish girl that she would send her “to one of your gas chambers” as a punishment for jumping the lunch queue.

The incident occurred earlier this year at the girls-only North London Collegiate School, when one of the pupils apparently tried to join the queue at the dining hall by unhooking a rope barrier.

The girl, aged 17 at the time, was stopped by a teacher with whom she had had little previous contact and told: “Don’t do that or I’ll have to send you to the back of the queue or to one of your gas chambers,” according to reports in the Mail on Sunday.

Download the new Independent Premium app Sharing the full story, not just the headlines

The school said it had been made aware of the allegation and, after seeking legal advice, taken “appropriate action”. It has not identified the teacher or elaborated on what its measures involved.

The incident was apparently overheard by a large number of pupils, and was reported by another family to the Community Security Trust, a group which is devoted to combating anti-Semitism and represents the Jewish community on a range of issues.

The trust’s communications director Mark Gardner said: “This would be highly offensive in any circumstance, but to be directed at a pupil by a teacher is unheard of and makes it far worse.

“We are working with all parties to resolve the matter.”

The father of the girl, who is now studying for her A-levels and asked not to be identified, called for the school to publicly condemn the incident as “unacceptable” and said there had been a lack of transparency over the disciplinary process.

The school issued a statement which read: “North London Collegiate School is proud of its rich, multi-cultural history and celebrates equality and diversity within the school community. The school was recently made aware of an allegation of an offensive statement made by a member of staff. The school promptly commenced an investigation.

“Having reached a determination and sought specialist legal advice, appropriate action was taken.”