The resignation of Jonathan Miller as headteacher of JFS , the country's largest Jewish school, has ended weeks of uncertainty after his unexplained absence since the start of term.

Mr Miller, who has led the London secondary school since 2008, wanted to "explore other professional opportunities", parents were told this week in a letter from the chairman of governors Steven Woolf.

But the governors maintained what one source close to the north-west London school called an "absolute clampdown" on giving more detail about the headteacher's departure.

Parents and staff had been told during the Pesach holidays that Mr Miller, who joined the school as a chemistry teacher in 1984, had taken a leave of absence and would not be dealing with school business for "the next few weeks".

Debby Lipkin, a schools improvement specialist who arrived as a consultant at the school in the middle of last term, will act as executive head of the school for the next 15 months alongside interim headteacher Simon Appleman.

Parents were informed that governors would now "undertake a wide-ranging search for the highest calibre leaders" longer term.

A farewell event for Mr Miller is to be held towards the end of the school year.

In his letter to parents, Mr Woolf, who became chairman of the 2,000-pupil school last year, celebrated Mr Miller's "many achievements and successes, including outstanding examinations results".

The school is due to receive a return visit from Ofsted soon following a critical report two years ago which downgraded JFS from outstanding to a school that "requires improvement".

On Tuesday, following the announcement of Mr Miller's resignation, Lord Levy, the president of JFS, addressed staff at a special meeting.

One insider said that Lord Levy had delivered a much-needed boost to morale with an "inspiring call to arms". Citing Leicester's City triumph in recently winning the Premier League, the peer urged teachers to believe that the school could get back to the top after its Ofsted setback.