Three determined schoolchildren who took on the police over controversial “kettling” tactics have lost their court clash – but they say it proves young people can “stick up for themselves”.

While their peers might be more worried about Facebook updates and the latest Hollyoaks plotlines, bold 16-year-old Adam Castle, his sister Rosie, 15, of Yerbury Road, Upper Holloway, and friend Sam Eaton, 16, of Loraine Road, Holloway, went to the High Court to battle the Metropolitan Police over last year’s student fees protests.

The trio argued police acted unlawfully in keeping children hemmed in for hours – but their case was thrown out on Thursday.

Adam, of Yerbury Road, Upper Holloway, who goes to Acland Burghley School in Burghley Road, Tufnell Park, said: “We’re very disappointed the judges didn’t see that the kettling of children for such a long time was completely unnecessary and not proportionate. We hoped we could get some justice for what happened.”

The teenagers had spent seven-and-a-half hours in Whitehall penned in by police in freezing conditions without food and water on November 24, along with thousands of other children, but the court ruled the Met’s actions were reasonable.

Adam, a former pupil of Yerbury Primary School, in Foxham Road, Upper Holloway, said they were looking into an appeal and added: “I’m pleased we managed to do it. I never thought children could do this sort of thing. Hopefully it shows they can’t do whatever they like to children.

“Just because we’re younger, it doesn’t mean we’re not going to stick up for ourselves.”

Adam and fellow Acland Burghley student Sam both had stunning GCSE results hauls recently, gaining 12 and nine A*s respectively.

Jo Armitage, headteacher at Acland Burghley School, said: “I’m really proud of Adam and Sam. I think they’ve shown themselves to be excellent role models for other young people.”

A spokesman for the Metropolitan Police said: “We welcome the decision. The court has acknowledged that the Whitehall containment was ‘necessary, proportionate and lawful’ and not prolonged for any unlawful purpose.

“The ruling also found that repeated efforts were made to identify children within it, particularly those in school uniform.”