Spy agency GCHQ is celebrating their centenary today.
To mark the historic occasion, the intelligence post has unveiled five unlikely locations across the UK where it has carried out its work over the last 100 years.
However, looking to the future, up to 500 recruits will start their careers with GCHQ by the end of this year in the new Manchester office .
But do you think you have what it takes to work as a spy?
You can now test your abilities with some puzzles created by the agency in the quiz below, which you can find in their book The GCHQ Puzzle Book II.
To help you on your way, GCHQ does have some tips and tricks on solving brainteasers. They are as follows:
Cryptic crossword clues
"A cryptic clue leads to its answer as long as it is read in the right way. What the clue appears to say when read normally is a distraction and usually has nothing to do with the answer," says GCHQ.
"The challenge is to find the way of reading the clue that leads to the solution - look out for indicators than an anagram is included. Or perhaps there are hidden codes within the words. Could the letters be substituted for numbers?"
Sayings/Phrases
"Think about how the words in a puzzle might be used in other common sayings phrases. Maybe they have alternate meanings, or opposites? Or perhaps they share a common property with other words and can precede or follow the same word," says GCHQ.
Try the quiz here:
