A judge has accused an east London council of “overwhelming failures” after two children were prevented from attending school and kept prisoner in their home for more than 14 years, despite their parents being well known to social services.

The boy and girl were aged 14 and 16 when they phoned the NSPCC themselves to report that they had never had any education or attended medical appointments.

At the father’s sentencing for child cruelty and neglect on Tuesday, Judge Sandy Canavan described the case as a “complete tragedy”.

The siblings entire education had been limited to “colouring in” with their grandmother and they had pieced together that their life was “not right” through watching television, Snaresbrook Crown Court heard.

Police removed the “malnourished” children from the home in Waltham Forest in June 2018 after being tipped off by the NSPCC.

But they remain effectively illiterate and find it difficult to socialise and make friends because of the years of schooling they missed, the court heard.

Judge Sandy Canavan said she “could not comprehend” how the children had been missed by Waltham Forest Council, considering both parents had “significant limitations” because of their upbringings and health problems and the family had never made any application to home school them.

The parents, who cannot be named for legal reasons, had already had one child taken into care in 2001 due to allegations of neglect and the health problems of the mother and grandmother were known.

Judge Canavan said: “It is a tragedy, a complete tragedy. Their life chances have been so severely limited by what has happened. They are going to carry the consequences of those formative years throughout the rest of their lives.”

She added: “These children went completely under the radar. On the face of it there appears to have been an overwhelming failure by the local authority.”

Judge Canavan said the father was a man of “limited capabilities” but knew his children should have been in school.

She sentenced him to a two-year community order and said the probation service will put a care plan in place for him.

The children remain in care.

In 2019 an independent serious case review found a dozen missed opportunities where social services could have stepped in sooner to help the siblings.

The report said the teenagers were “pale and with their appearance suggestive of being malnourished” when found by police and told officers they had to hide when people visited the home.

It noted they had missed multiple medical check-ups as a babies and could not recall ever visiting a dentist.

A doctor had tried to raise concerns about the teenage girl’s welfare in 2016 with the council’s safeguarding team, but the referral was never completed after “a discussion with a social worker”, the report found.

Met officers had also been called out twice to the family home, including in February 2008 when the boy, then aged four, was found walking the streets alone wearing only a T-shirt and nappy, according to the report.

After he was returned to his parents “there is no record of the police requesting to see the other children in the household or liaise with other agencies”.

The father admitted child cruelty and neglect at an earlier court hearing. Charges against the mother were dropped.

Dave Peplow, independent scrutineer for Waltham Forest Safeguarding Children Board, said: “This was an exceptional and shocking set of circumstances that led Waltham Forest safeguarding partnership to undertake a serious case review in 2019.“Since the review all recommendations have been implemented and, despite delays to anticipated changes to statutory guidance, there are now more robust processes in place locally for young people known to ensure that elective home education is suitable for their needs including their social and emotional wellbeing.

“The pandemic has brought the implications of home education further to the fore and the council has maintained consistent oversight of vulnerable children educated at home throughout this time.”