The number of kids being home-schooled in Hackney has rocketed in the space of a year, raising fears academies might be “washing their hands” of difficult children in an illegal practice known as “off-rolling”.

Hackney’s academies – schools run outside of council control – saw what is thought to be the biggest increase in the country with a 238 per cent leap of children moving into home education last year, according to a report drawn up by the children’s commissioner for England, “Skipping School: Invisible Children”.

Newham in second place saw a 112pc increase.

The rise at local authority run schools in Hackney over the same period was just 21pc.

“The analysis sheds new light on the oft-cited claim that academy chains are off-rolling more than LA run schools,” Anne Longfield OBE, notes in her report about how children “disappear” from England’s schools.

Schools can only exclude pupils on disciplinary grounds, not for low attainment or if the child has emotional needs they feel unable to meet.

While some parents opt out from the education system voluntarily, Ms Longfield points out: “It is sometimes schools themselves that put pressure on parents to remove children who don’t fit in. This practice, known as off-rolling, can amount to informal, illegal exclusion. This can be because the school is focused on improving overall exam results and not the individual needs of each child.”

Referring to schools nationally, she added: “Some schools are believed to have pro forma letters ready for harassed parents to sign, agreeing that their child would be better off home educated when they come to meet the head after yet another problem.” She criticised as “unacceptable” the way that “some schools are washing their hands of children – particularly the vulnerable” in the report, which looked at 11 local authority areas with a high number of fixed exclusions – Hackney among them.

This month police commissioners and London’s mayor wrote to the PM to warn that formally and informally excluded pupils are being “sucked into criminality”.

Worryingly, children off-rolled into home education do not show up in school records, and just disappear from the roll. Exact figures are unknown because parents do not have to register home-educated children. Last year the national figure stood at an estimated 52,770, and is thought to have doubled in five years.

Ms Longfield notes many school practices make it harder for children with special needs to fit in.

“These include hard line behaviour policies in which children receive two or three warnings for any breach of the behaviour code, however big or small, before being sent to a seclusion room or isolation booth to work in silence for the rest of the day,” she wrote. “Policies like this might improve conduct among the majority of the pupils, but can be counter-productive when applied without any flexibility for other pupils, including those with additional needs.”

A consultation is currently being held by Ofsted as to whether off-rolling could be included in a new inspection framework from September, which would mean a school would be deemed “inadequate” if it were found to be illegally doing so.