GCHQ invites the public to be Christmas code crackers

GCHQ has challenged the “wise men and women in your household” to solve its annual Christmas card puzzle.

The intelligence service employs the best problem-solving minds to keep the country safe and the puzzle is vital for testing the skills of codebreakers.

Jeremy Fleming, the director of the security agency, has revealed a Christmas card containing one of the “most fiendish puzzles to date”.

This year it is in the form of a festive bauble which contains a hidden message, and those attempting it will need to complete a series of letter sequences before plotting their answer from an enigmatic “frosty” location.

A GCHQ spokesman said: “Problem solving is at the heart of what we do.

“Taking on this Christmas cracker gives puzzlers an insight into the skills you need to be a GCHQ analyst.

“Bring together a mix of minds by sharing it with the wise men and women in your household to find the solution.”

The puzzle requires the solver to find the missing letter at the end of nine seemingly random sequences on the Christmas card, which shows a stylised bauble with an arrow running through it.

The card instructs codebreakers to: “Plot your single-letter answers in the corresponding golden nodes on the bauble.

“Follow the flow of arrows from somewhere frosty to unblock the message.”

The challenge was designed by GCHQ staff who use puzzles to develop their skills in the world of cyber security.

The Daily Telegraph will reveal the answers tomorrow.

Along with the Christmas challenges the agency has raised more than £500,000 for mental health charity Heads Together through the sales of GCHQ Puzzle Books.