A prestigious grammar school rated the top in the country for Oxbridge offers has been slammed in a new Ofsted report for its toxic culture.

Colchester Royal Grammar School was inspected in May with officers finding that a "significant number" of pupils at the school felt "uncomfortable" or "unsafe".

Ofsted rated the school as inadequate after previously rating it good.

Earlier this year The Telegraph rated it the top grammar school for Oxbridge offers in the country.

Despite this accolade, pupils were said to feel reluctant to pass on their concerns to staff, leaving leaders unaware of the extent of difficulties faced by pupils.

Ofsted slammed the school for a culture which didn't promote "equality and respect" with gender, race and sexual orientations among the reasons given for why pupils were badly treated at the school.

"Some pupils do not feel safe in school because of a culture which allows them to be victimised for being themselves," read the report.

Staff were criticised for not preparing of boys well enough for girls entering the school, which they only do at sixth form.

Inspectors also condemned the ineffective safeguarding at the school.

There were some positives with inspectors highlighting that teachers inspired pupils' interest in academic subjects and that pupils studied at a high level after leaving.

East Anglian Daily Times: Scarlett Mansfield had previously raised concerns about the school and called for the headmaster to resignScarlett Mansfield had previously raised concerns about the school and called for the headmaster to resign (Image: Scarlett Mansfield)

Former student Scarlett Mansfield raised concerns about the school in a blog post which cited anonymous experiences of female students, including sexual assaults which allegedly happened during their time at the school, as well as sexism.

Miss Mansfield said she was pleased that Ofsted had recognised what was going on at the school.

“Going forward I am of the opinion that the headmaster and the chair of the board of governors should resign,” she said.

Headmaster John Russell said: “Our school demands the very best of our students and ourselves, and the Ofsted inspection is a very difficult report to read.

“We have never shied away from the fact that we believe that there is always more that we can, and want, to do for our students. We continually strive to improve every aspect of life at CRGS, and we have worked hard to adopt best practice in creating an environment where our students can flourish.

"Inspectors rightly saw the quality of education and our students’ attitudes to learning as being a real strength, but during their inspection they raised concerns about issues such as the delivery of PSHE curriculum, and some aspects of wider behaviour.

“These areas are important, and their findings about these aspects are known as 'limiting judgements' - meaning that they dictate the overall grade. We did not show our strengths in some of those limiting judgements. As such, the overall grade was significantly impacted.

“Therefore, while we feel that the strengths of the school are not fully reflected in the report, the Ofsted Framework is the measure against which all schools will be judged – and we listen to what the inspection team found, and continue to act upon that. Our focus has to be on driving forward improvements and building on our many strengths and successes.

“Key to this will be continuing to enhance our culture where our students show greater respect for themselves and for others, and eliminating the use of derogatory and discriminatory language. To support this we will further develop effective reporting systems, particularly around how students raise any concerns that they may have.

“While this is a very sad day for our school, it does not mean that we are not proud of all that our staff and students achieve. Our students show impressive qualities, and we will continue to work with pace and purpose to support them and enhance the culture of the school.

“Going forward, there will be further discussions about what this outcome means for CRGS. We are working with the Department for Education and Regional Schools Commissioner to discuss the increased focus that the school will be under, and how we continue to move forward for our community.”