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See if you can solve these fiendish brain-teasers written by GCHQ spies

Rob PriceOct 29, 2016, 15:10 IST

GCHQ

Are you smarter than a British spy? Then prove it.

GCHQ, one of the UK's spy agencies, is publishing a "Puzzle Book" of riddles and brain-teasers written by British spooks.

The puzzles range from mathematical riddlers to lateral thinking problems and photo-association games.

The book is being published by Penguin for £12.99, and is out now.

We've republished three of the puzzles below. Have a go at each one, and when you think you've got it (or you give up), then scroll down for the answer.

Good luck!