CLIMBER:So I'm here at base camp. CLIMBER:It's seven am. CLIMBER:And I am so ready for this challenge. CLIMBER:In just a few hours, I will be at the summit. CLIMBER:So I set off about an hour ago, ...

MARCUS DU SAUTOY:'You might think that catching criminals 'is all about finding physical evidence. 'Fingerprints, DNA. MARCUS DU SAUTOY:'But even when these clues aren't available, 'a mathematical ...