When Millan Sachania arrived in September to become the new headmaster of Immanuel College, it “felt like coming home”. An understandable sentiment for the music scholar, now 50, since he previously spent eight years at the Bushey school.

A few things may have changed since his first tour of duty — but the spirit remains the same. “There is no school I have visited in which the pupils have such verve, dynamism and self-confidence  -  in the nicest possible way,” he reflected.

“In my first day back, I walked around the school and the pupils talked to me naturally, in the most friendly manner. I had conversations about Lucien Freud with one student, I went to the art room and the girls started talking to me about their artistic experiences of going to exhibitions, I went to another room and I had a discussion about a recent visit to a Shakespearean play.

“In other schools, students aren’t so forthcoming and neither do they reflect so intelligently on their experiences. That has not changed.”

When he left in 2011 to become headteacher of Streatham and Clapham High School — an independent girls’ school run by the same trust as South Hampstead —- he believed that Immanuel’s governors “were interested in pursuing me for the headship here of Immanuel” but he was keen to gain fresh experience elsewhere.

It was when he returned for the first time after 10 years to have tea with Immanuel’s then headteacher Gary Griffin — who retired last December —  that he thought, “Wow! I remember what a wonderful school this is.”

While he has made his career in the independent sector, it was not a milieu familiar to him as a child. His parents were products of the Indian diaspora in East Africa, arriving in the UK from Tanganyika, as it was , via Zambia in the 1960s. His father opened a garage and built up a business repairing cars.

Dr Sachania went to the local comprehensive in Shepperton but because it didn’t have a sixthform, he did his A-levels at Esher College. “That was the making of me. The principal asked had I thought of going to Cambridge. I thought, ‘I can’t go to Cambridge, that’s for private school people’, but I was encouraged and got in.”

He excelled, not only gaining a double-first in music but going on to complete a doctorate; he is the author of some 30 scholarly books, writing on composers such as Stravinsky and Poulenc. He lived in the university city for seven or eight years and “could have spent the rest of my life there” but decided to train as a teacher and got his first job as head of music at a girls, school in Windsor in 1999.

In 2003, he came to Immanuel as head of sixthform and was promoted to assistant head in 2007. In the 10 years he ran Streatham and Clapham, the school grew under a leadership, he said, was influenced by what he had learned at Immanuel. “The spirit of Torah im derech [Torah combined with the best of secular knowledge], the motto of the school, has flowed through my veins… and I took that through all the things I have done.”

The sense of community that he had found at Immanuel, the “spirit of tzedakah”, the inquisitive approach to learning exemplified in chavruta — close study of Jewish texts — all made a lasting impression on him.

He also became a lead inspector for the Independent Schools Inspectorate, enabling him to see what was happening in other schools.

The past decade has been a good one for Immanuel with a significant rise in numbers. “The sixthform is 140, the biggest the school has ever known,” he said. The academic profile has improved, he believes, with more even results from year to year — a consequence of a more stable intake.

When he left, boys and girls were taught in separate classes but now as a result of the 2010 Equality Act, they mostly learn together. “When I left there was no issue about smartphones,” he said. “Now the pastoral life of the school is very much guided by keeping people safe online.”

Another change has been the greater prominence given to informal Jewish education and the activities centred around “the beit”, the beit midrash.

Nevertheless, as one member of staff said, last year was a difficult one, with a restructuring that resulted in the departure of a number of staff.

The actual number of posts lost were “very few”, he said. But the reorganisation has led to a smaller senior leadership team.

After last year’s shake-up, he will maintain “some stability”, while reviewing the progress of the changes made to see what “has worked” and what has brought “unintended consequences”. He will also begin plotting a strategy for the school over the next three to five years.

He wants to develop partnerships and outreach — not only within the Jewish community, but also locally beyond the community and internationally with institutions in Israel or USA.

Another area is to look at how “to give more opportunities for pupils to develop and project leadership qualities”. He also wants to make sure that Jewish life and learning,which lies at the heart of the school’s identity, reaches all its pupils across the spectrum of observance, “not just a few”.

An estate development plan is also in its early stages for the school, which among things has the challenge of maintaining the grade 2-listed building in which his office sits. But one new facility he has been happy to see are the floodlights for the all-weather pitch.

It may be too soon to spell out any proposal in detail. But schools have to be ready to change, he said. “Any institution that doesn’t embrace change and, indeed, be the agent of change rather than the victim is going to be left behind. My aspiration for Immanuel College is that the school should be the agent of change for the good.”