The latest weapon in the fight against international terrorism has been developed by 14-year-old schoolgirls.

Pupils from St Philomena’s Catholic School for Girls, in Carshalton, won first prize in the Lionheart business challenge beating 13 schools from various parts of the UK, after developing an idea for a sensor that can detect radioactive materials and chemical explosives.

The 10-strong group went to Liverpool to compete in the business challenge, where they had to come up with the idea for a device to fight terrorism, produce a business plan for it and show where and how it would be used.

Nigel Goddard, the school’s assistant principal, said: “They had to develop a concept for a device that would help prevent terrorism.

“They came up with the idea of a sensor that could detect radioactive materials and chemical explosives and the idea to promote it for the 2012 London Olympic Games.”

They made a formal presentation to a panel of judges, including two managing directors and the Chief Superintendent of Merseyside Police.

Mr Goddard said: “The results were announced at a formal evening dinner, when the St Philomena’s team were both delighted and surprised to learn they had won and that they would be able to return to school with the Lionheart trophy.”

The annual challenge is run by a private company, Field Lockhart Associates, from Glasgow, and this year it was sponsored by the Chartered Institute of Management Accountants.

Johanna Bryson, the challenge’s general manager, said: “We have a team of experts who helped the children with their projects. Every idea we choose in the end has commercial potential, although we as a company do not invest in developing them.”

Tom Brake, MP for Carshalton and Wallington, said: “I must congratulate St Philomena’s pupils on their business acumen and for winning this challenge.

“The task set for them, designing a device to fight terrorism, is a sad reflection on our times. Gone are the days when pupils were required to design badges or cards, they must now help us win the war on terror.”

About 350,000 pupils from all over the UK took part in the challenge.

St Philomena’s winning team members were Ellen Casey, Sanah Alban, Beth Ridgely, Ciara Bowdler, Alannah Flannery, Lucy Lee, Robyn Harwood-Lewis, Daisy Hall, Claire O’Shea and Louisa Selwood.

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