DirectorAnne Keast-Butler, who is the first woman to lead GCHQ, held a competition for over 500 schoolchildren to design the cover of the spy chief's Christmas card....
The spy agency's "ChiefPuzzler" said the notoriously tricky puzzles are designed to test "the same blend of skills our teams use every day to keep the country safe” ... .
Get ready to solve the latest GCHQ puzzles and brainteasers, as the ChristmasChallenge returns. Now in its 10th year, the Christmas Challenge is designed by GCHQ's own codebreakers to give your brain a festive workout.