An aspiring doctor who was referred to Prevent over “misinformed” claims that he was “obsessed” with killing David Cameron must have his personal data deleted by the Metropolitan Police, the High Court has ruled.

The boy – known only as II – was 11 when a tutor raised concerns in December 2015 that he allegedly wanted to kill the then prime minister, had spoken about “America being evil” and said he “liked Game Of Thrones because of the beheadings”.

Officers with the Prevent anti-radicalisation programme spoke to his mother, NK, who said her son had recently written a letter he wanted to send to Mr Cameron which “spoke of peace and unity throughout the world”.

She also said she “did not let him watch Game Of Thrones so he wouldn’t know anything about the violence in the show”, and told police it was “frightening and saddening to me that you are potentially viewing II as a possible terrorist in the future”.

Prevent officers concluded “there were no radicalisation/counter-terrorism concerns”, that the tutor’s concerns “appear to be a misunderstanding” and closed II’s case in June 2016.

But in April 2019, the Met decided to retain II’s personal data, meaning it would be held on 10 separate databases, some of which can be accessed by Home Office officials and several local authorities as well as counter-terrorism officers, until at least 2022.

The boy – who is from east London and is now 16 – took legal action against the Met, claiming the retention of his personal data was a breach of his right to privacy and a breach of the Data Protection Act.

In a witness statement, his mother said that II is “a bright young man, with plans to apply to a top university in the UK and to train to become a medical doctor”.

She added: “He is afraid that at some point in the future the untrue data may affect any potential police record searches and could give rise to further monitoring of him, and jeopardise his future prospects.”

The Met said the retention of II’s personal data would have a “minimal impact” on him, and there was “no way” it would be shared with “any educational institution or any prospective employer”.

But II’s lawyers pointed out there had been “no guarantee that the data will not be disclosed to third parties”.

In a judgment delivered on Thursday, Mrs Justice Steyn found that “no policing purpose for continuing to hold the claimant’s personal data has been demonstrated” and that its retention breached II’s right to privacy and the Data Protection Act.

The judge said the Met had “underestimated the impact of the interference with the claimant’s privacy rights entailed in retaining data about his alleged views and statements when he was 11 years old”.

She added: “Retention alone means that the data can be accessed by (Metropolitan Police Service) officers, counter-terrorism officers nationally, local authorities and Home Office colleagues, across 10 databases.”

Mrs Justice Steyn also said there was “no guarantee that the claimant’s personal data will not be disclosed to third parties”, which she said “engenders fear in a 16-year-old boy that he may be tagged – wrongly – as a supporter of terrorism”.

In a statement after the ruling, II’s mother said: “A dark cloud had loomed over my family for the past five years.

“My son had grossly misinformed allegations cast against him that could have had the potential to destroy his future.

“To constantly live, not knowing whether false information about your child, accessible by public bodies, would be shared, hampering his chance to live freely in a country you have always known to be home, is beyond heart-breaking.

“For us, this cloud passed, because we knew where and who to seek advice from. We were guided by a brilliant legal team – but what about those who don’t know?”

II’s solicitor Bharine Kalsi, of Deighton Pierce Glynn, said: “The court today has found that there was ‘no policing purpose’ for the retention of data concerning II – data which alludes to radicalisation, but which our client has always maintained is untrue.

“Today’s judgment means this data will no longer cast a worrying shadow over II’s bright future, particularly as there is no guarantee that it would not be shared with other organisations and institutions.

“It is now time for the authorities to look at their exercise of power under the Prevent strategy, which continues to unjustly target innocent individuals, in particular children from the Muslim community.”

A Met Police spokesman said: “We note the court’s judgment in this matter and will now take time to consider this in full.”

By Sam Tobin, PA