Cheltenham-based GCHQ has launched its annual Christmas Challenge, and said it is the toughest yet!

The challenge has been designed for schools and colleges, but GCHQ is encouraging everyone to give it a go pit their wits against its puzzlers.

The challenge is in the form of a Christmas card, sent by GCHQ's director, Anne Keast-Butler, to partners around the world.

It features seven complex puzzles, masterminded by the organisation's in-house puzzlers. Puzzles are designed to test a range of problem-solving skills and encourage teamwork to reveal the final festive message.

The card design includes a nod to 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.

Anne Keast-Butler, GCHQ director, said: "Puzzles have been at the heart of GCHQ from the start. These skills represent our historic roots in cryptography and encryption and continue to be important to our modern-day mission to keep the country safe.

"GCHQ's history at Bletchley Park is represented in this year's Christmas card as a reminder of the role this historic place has played in our wartime efforts, but also as home to this year's AI Safety Summit.

"Our puzzlers have created a challenge which is designed for a mix of minds to solve. Whether you are an analyst, an engineer or a creative, there is a puzzle for everyone. This is one for classmates, family and friends to try to solve together."

Head to the GCHQ website to give it a go before the answer is revealed tomorrow (December 15).

Image credit: GCHQ