Schoolchildren across the country will put their puzzle-solving skills to the test after GCHQ launched its annual Christmas Challenge.

The UK spy agency sent its Christmas card with the challenge, fronted by a rare image of a snow-covered Bletchley Park, to more than 1,000 secondary schools on Thursday.

It includes seven increasingly complex puzzles that test skills such as codebreaking, maths and analysis, and encourages pupils to work as a team to reveal the final festive message.

The challenge is the toughest to date, and encourages people to pit their wits against schoolchildren
The challenge is the toughest to date, and encourages people to pit their wits against schoolchildren (GCHQ/PA)

A maths-based bonus puzzle has also been included, which has been described as the toughest to date.

Bletchley Park was the wartime home of GCHQ and the featured image, taken in January 1940, was discovered in the personal family album of Joan Wingfield, who worked on breaking Italian naval codes.

Many of the world’s leading politicians gathered in Bletchley Park last month for a two-day summit on the safety of artificial intelligence (AI).

GCHQ Christmas Card Challenge
(GCHQ/PA)

GCHQ director Anne Keast-Butler 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.”

Now in its third year, the challenge, which is available on the agency’s website, aims to provide an insight into GCHQ’s work and inspire young people to study Stem subjects.

Colin, chief puzzler at GCHQ, said: “Our mission relies on people thinking differently and finding inventive ways to approach challenges.

“Like the work at GCHQ, solving the puzzles on the card requires a mix of minds, and we want to show young people that thinking differently is a gift.”