Fancy a challenge? GCHQ have issued a Christmas brain-teaser and announced it will be asking players to make a donation to the NSPCC.
Director of GCHQ, Robert Hannigan, included a brain-teasing puzzle in his Christmas card which has also been published online.
Participants have to fill in a grid-shading puzzle to unveil a picture, which is the first in a series of increasingly complex challenges. Coverage includes BBC, Daily Mail, Daily Express, and Daily Telegraph.
Or, if you want something a little less challenging take part in our quiz, ‘How Christmas are you?’.