The number of ultra-Orthodox Jewish schools believed to be operating illegally in the east London borough Hackney now outstrips those which are legal, the council has suggested for the first time.

The admission by a senior education official at a furious council meeting on Wednesday night has intensified concerns for the safety and welfare of hundreds of children who are being taught in often isolated conditions with little contact for the secular world.

Andrew Lee, Assistant Director of Education Services at Hackney's education authority the Hackney Learning Trust, said his team had now identified “possibly 35” unregistered ultra-Orthodox schools in the borough, compared with 33 that are legal.

However, he also said the suspected number of illegal schools could fall. At a meeting of Hackney’s Children and Young People Scrutiny Commission on Wednesday, he said: “[The 35] are establishments where our officers have passed by on a number of occasions at various times during the day and have seen a significant number of young people entering and leaving.

“Perhaps 13 of those settings may be linked to some of the 33 registered settings, which would bring the number down somewhat.”

But his comments were met with anger from Councillor Abraham Jacobson, a committee member and Orthodox Jew.

He said: “I’m streetwise. I know what goes on. I think we're talking possibly about 12 – maximum. They tend to move from place to place.”

Hackney is home to a large ultra-Orthodox Jewish Charedi community, which is regarded as insular and practices a strict 19th-century interpretation of the faith.

Engagement with the secular world is for many deeply taboo.

The Independent has spent months investigating illegal schools in the borough.

Those forced to attend illegal schools have reported that they are not taught English or anything secular so they can instead focus on studying the Torah.

One former pupil at an illegal schoool in Hackney told The Independent he was regularly subject to “physical and psychological abuse”.

“They went to extreme length to stop us learning English,” he said. “Education is all about preparing people to make their own choices. The very ethos of these schools is to do the exact opposite and to isolate people from secular society.”

An investigation by The Independent earlier this year found more than 1,000 children in Hackney are currently missing from schools – and at risk in one of the illegal institutions identified by Hackney Learning Trust.

Thousands more over the years have gone missing.

We found Hackney Learning Trust, Hackney’s education authority, destroyed evidence of children being educated in illegal faith schools at the request of religious institutions.

But at Wednesday's council meeting, there was little evidence of cooperation between religious institutions and government authorities, including schools watchdog Ofsted, in Hackney.

In a tense exchange, Rabbi Avraham Pinter, a spokesperson for the London Jewish community, accused Ofsted of “targeting the Jewish community” and ignoring the “end result” after pupils had been through the illegal school system.

In response to concerns about the physical safety of children in illegal schools, he said: “I believe that there is an agenda and all this talk about safety is really about social engineering.”

Rabbi Avraham Pinter attacked Ofsted at a Hackney council meeting on Tuesday night (Hackney Council)

Rabbi Pinter, who represents Hackney on executive of the National Association of Orthodox Jewish Schools told Ofsted inspectors that it was “offensive and very patronising” to suggest ultra-Orthodox children in illegal schools were not getting “the best”.

“In the general community, 30 per cent of children before the age of 16 have experimented with drugs. Is that success? Anybody who knows Jewish parents and Charedi [ultra-Orthodox] parents knows they want the best for their children. There might be a disagreement about what it should be ... I would look at the end results [for Charedi children] and I'm not disappointed.”

The committee was also urged to look at the “big picture” by Chaya Spitz, a representative from Orthodox Jewish charity the Interlink Foundation. “There is not an issue with welfare and safeguarding [in the Charedi community],” she said. “At the end of the day it's about what parents want.”

But Rabbi Pinter and Ms Spitz were told by Ofsted's London regional director Michael Sheridan: “I’m sorry you're upset by wanting the best for young people but I will never apologise for that.”

Ofsted’s deputy director for unregistered schools Victor Shafiee added: “We are asking them to work within the law.”