The front of one of the security capsules opened, she stepped inside, and was briefly enclosed. Then, as if she’d travelled light years in an instant, the rear door slid open, and she stepped out into another dimension. Thames House was a hive, a city of steel and frosted glass, and Liz felt a subtle shift inside herself as she crossed its security threshold and was borne noiselessly upwards to the fifth floor.

The lift doors opened and she turned left and moved at speed towards 5/AX, the agent-runners’ section. This was a large open-plan office lit by strip lights and lent a faintly seedy character by the clothes stands that stood by each desk. These were hung with the agent-runners’ work clothes-in Liz’s case a worn pair of jeans, a black Karrimor fleece, and a zip-up leather jacket. Her desk was spare-a grey terminal, a touch-tone phone, an FBI mug-and flanked to one side by a combination-locked cupboard from which she took a dark blue folder.

“And, coming into the home straight…” murmured Dave Armstrong from the next desk, his eyes locked to his computer screen.

“Courtesy of the bloody Northern Line,” gasped Liz, spinning the cupboard lock. “The train just… stopped. For at least ten minutes. In the middle of nowhere.”

“Well, the driver could hardly sit and smoke a joint in the station, could he?” asked Armstrong reasonably.

But Liz, folder in hand and minus coat and scarf, was already halfway to the exit. En route to Room 6/40, one flight up, she hurried into a washroom to check her appearance. The mirror returned an image of unexpected composure. Her fine, mid-brown hair fell more or less evenly about the pale oval of her face. The sage-green eyes were a little bruised by fatigue, perhaps, but the overall result would serve. Encouraged, she pressed on upwards.

The Joint Counter-Terrorist group, of which she had been a member for the best part of a year, met at 8:30 a.m.