Cheltenham-based intelligence agency, GCHQ, is putting schoolchildren to the test with its Christmas puzzle.

The festive brainteaser features on a Christmas card sent by Sir Jeremy Fleming, GCHQ director.

It is designed to test codebreaking skills, with secondary schools across the country trying to solve the puzzle, as reported by the BBC.

Sir Jeremy advised that children need to "combine a mix of minds to solve the seemingly impossible".

The Christmas card features seven puzzles, aimed at testing pupils' knowledge of key subjects and their ability to work as a team.

The puzzles are based on the key skills needed at GCHQ to help keep the country safe: languages; engineering; codebreaking; analysis; maths; coding; and cyber security.

Once all the puzzles are solved, children need to use the design on the front of the card to assemble the answers to form three locations. Joining the place names together will reveal the final answer.

Schools interested in taking part can find a resource pack on the GCHQ website.

Has your school tried the puzzle? Have you cracked the code? Let us know at news@moosemarketingandpr.co.uk.