Doing the GCHQ Christmas Challenge? Let these experts help you.

Still scratching my head over it. The GCHQ Christmas Challenge?

This year the public has been challenged to decode the names of UK landmarks, testing skills including code-breaking, maths and lateral thinking.

The annual brain teaser is meant to tickle the neurons of those who hope to work in intelligence, and it comes in the form of a Christmas card, sent by National Intelligence Agency Director Anne Keith Butler.

To help you sort it out, we’ve talked to a few surprising experts to pick their brains about how to navigate testing challenges.

Read on and don’t worry – we haven’t given the answers.

The only advice Ms Keith Butler gave to BBC Breakfast on Wednesday was to work in a team and “bring a rich mix of minds”.

Bobby Siegel, math teacher, author and challenge devotee, agrees with this view.

“We all remember from our school days, different people have different talents,” he says. “Some people may think in a mathematical way, others are visual learners or more linguistic.

“It shows that many different skills matter.”

The first – and easiest – question consists of five images, representing a place name.

Maths teacher Susan Okirec, who writes puzzles for BBC Radio 4, said she was initially daunted by the challenge.

“I thought, GCHQ – no way!”

But she managed to crack the code by reading it out loud.

“I was looking at it and thinking, what does it look like?

“Then I thought, this has to be a niche – to narrow it down.”

Dr. Barry R. Clark, author of several puzzle books, took about two minutes to solve the first puzzle.

But the second reason was a bit more head scratching.

“My first thought here was the London Underground tube lines, because of the colours… but I was getting nowhere.”

He suggested looking at the columns instead and looking for possible connections.

A hard problem asks the puzzlers to calculate how far the quiz setters were from the numbers 1 to 20.

“It looks like it’s set up for some kind of rotation,” says Dr. Clarke. “You can probably start in the middle and work your way out to get one to 10.”

Mr. Siegel takes a distinctively two-pronged approach to the GCHQ challenge, which he says is the highlight of his “amazing year.”

“It may take hours or days, but let it sink in,” he explains.

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

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

“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 won’t ask you about things you don’t know.”

He added that while GCHQ staff create many puzzles that ask for specific knowledge, “they set each other up for their own personal amusement”.

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

The real challenge, he says, is to figure out what the puzzle is actually asking.

He explains: “Unlike sudoku or a crab crossword, it’s not clear what to start with in the puzzle – you don’t know what you’re decoding it. First you have to figure out what the question is. And then what is the answer?”

The full challenge can be viewed on the GCHQ website. Here