Doing the GCHQ Christmas challenge? Let these experts help you

Mr Seagull takes a specific two-prong approach to the GCHQ challenge, which he says is the highlight of his “puzzling year”.

“It may take a few hours or days, but let it incubate in your brain,” he explains.

“The first step is analytical or brute force. Take the puzzle, underline key words, work out what you do and don’t know.”

Alan Connor, the Guardian’s crossword editor and the puzzle consultant on BBC One’s puzzle-based detective series Ludwig, said not to worry about feeling ignorant.

“The thing to remember is that the person setting the puzzle wants you to solve it.

“A puzzle that’s presented to the general public is not going to be asking you for things that you don’t know.”

He added that while GCHQ staff make plenty of puzzles that do ask for niche knowledge, “they set those for each other for their own private amusement”.

“The experience that they want you to have is to feel you’ve achieved something because you’ve struggled a bit,” he adds.

The main challenge, he says, is to work out what the puzzle is actually asking.

He explains: “Unlike with a sudoku or a crib crossword it’s not clear what the puzzle is to begin with – you don’t know what it is you’re decoding. First of all you have to work out what the question is and then what the answer is.”

The full challenge can be viewed on GCHQ’s website here., external