Brits, your government needs you to solve this puzzle

Spare a thought for the British intelligence services. Every time they come up with a clever recruitment drive, their efforts are hampered by yet another off-putting death scene in a certain long-running spy drama. But relax, this particular ciphered job advert is entirely safe. It's been put out by the UK's monitoring service, GCHQ, which is altogether more 9 to 5 than MI5. You simply need to figure out the keyword buried in that daunting grid of characters, submit it via the 'canyoucrackit' link below, and a happy career in headphones and Herman Miller could be yours. On the other hand, people who claim to have beaten the puzzle seem underwhelmed by the response: all it got them, they say, was a shot at a £25k per year position that was already being openly advertised on the web. But, who knows, maybe those guys only think they cracked it?