A top-performing girls’ school has been branded “exceptional” and given the highest possible rating following its first inspection for six years.

Channing School in The Bank, Highgate Village, scored “excellent” in every category on Tuesday by the Independent Schools Inspectorate (ISI) – the government-approved body which holds to account some 1,200 private schools nationwide.

The school, for children aged between four and 18, has improved significantly since its last inspection in 2009, when it was rated “good” and only “sometimes outstanding”.

Headteacher Barbara Elliott said: “By rating Channing at the highest possible level in all areas, the ISI has given us an enormous vote of confidence and is a fitting tribute to the exceptional progress made by the school since 2009.

“My sincere thanks go to the expert inspection team, who described Channing teachers and staff as ‘inspirational’, to our governors, parents and supporters for their input into the consultation process, and of course, and in the words of the departing inspection team, to our ‘fabulous’ girls. I couldn’t agree more.”

The school received glowing praise for the “exceptional” quality of pupils’ achievements and learning, as well as the positive attitudes of students.

In the report, the nine-strong team of inspectors said: “At every stage of their education, pupils demonstrate the highest aspirations and an extremely positive work ethic: the school is definitely a place where it is ‘cool’ to work.”

Channing was rated excellent in all categories, including for pupils’ personal, spiritual, moral, social and cultural development – the category in which the Birmingham Trojan Horse schools failed.

Incidents of bullying were found to be rare, and the school’s cyber-bullying policy was highlighted as particularly effective.

It was only given one improvement to make before the next inspection: to continue to enhance the support of pupils with special educational needs.

Pupils are described as “exceptionally confident, articulate and intellectually mature in their outlook”, while those in the junior school are “highly articulate, thoughtful and insightful”.

The school was founded in 1885 for the daughters of Unitarian ministers, and tries to uphold the Unitarian ethos of inclusion and tolerance.