The Challenge is presented in the form of a Christmas card, sent by GCHQ Director, Anne Keast-Butler, to partners around the world (which includes Tom!).

Whilst the Challenge has been designed for schools and colleges, we’re encouraging the wider public to take on the challenge to pit their wits against our puzzlers. The year’s Challenge features seven complex puzzles, masterminded by our in-house puzzlers. They are designed to test a range of problem-solving skills and encourage the use of teamwork to reveal the final festive message.

The card design includes a nod to GCHQ’s wartime home at Bletchley Park with a rare image of the snow-covered mansion. It was taken in January 1940, before a photography ban was introduced there, and was discovered in the personal family album of codebreaker Joan Wingfield.

Download the questions for yourself at the link below (solutions will be available at the same link from 07:00 GMT on Friday 15th December). Good luck!