Somewhere in that building the last late-working executive is yawning and reaching for the door remote of his BMW. The cleaners have all gone home; the big servers hum blandly in their air-conditioned womb, nestled close to the service core of the office block. All I have to do is avoid the security guard and I'm home free.

A distant motor coughs into life, revs, and pulls out of the landscaped car park in a squeal of wet tires. As it fades into the night my pager vibrates again: GO GO GO. I edge forward.

No motion-triggered security lights flash on. There are no Rottweiler attack dogs, no guards in coal-scuttle helmets: this ain't that kind of movie, and I'm no Arnold Schwarzenegger. (Andy told me: "If anyone challenges you, smile, stand up straight, and show them your warrant card-then phone me. I'll handle it. Getting the old man out of bed to answer a clean-up call will earn you a black mark, but a black mark's better than a cracked skull. Just try to remember that Croxley Industrial Estate isn't Novaya Zemlya, and getting your head kicked in isn't going to save the world from the forces of evil.")

I squish through the damp grass and find the designated window. Like the briefing said, it's shut but not locked. A good tug and the window hinges out toward me. It's inconveniently high up, a good four feet above the concrete gutter. I pull myself up and over the sill, sending a tiny avalanche of disks scuttering across the floor. The room is ghostly green except for the bright hot spots of powered-down monitors and fans blowing air from hot CPU cases. I stumble forward over a desk covered in piles of kipple, wondering how in hell the owner is going to fail to notice my great muddy boot-print between the obviously confidential documents scattered next to a keyboard and a stone-cold coffee mug. Then I'm on the floor in the QA department, and the clock is ticking.