A man in a white coat was standing over one of the recording machines, checking line levels. He seemed relieved to see Villiers.

‘Thank God!’ he snapped. ‘I’m a scientist, you know, not a bloody gaoler.’

Villiers ignored the outburst. ‘This is Major Dreyfuss,’ he said. ‘And Major Dreyfuss, this’ – pointing his gun hand at the man – ‘is Henry Fagin, head of this … establishment.’

‘A bloody pawn more like,’ Fagin muttered, loud enough to be heard. He was still bent over his machines, moving from one to the next like a commander inspecting his troops.

‘What is this place?’ Dreyfuss said, looking around him. One hand still rested on Jilly’s shoulder, kneading the skin gently, calming her.

The reply came from Fagin. ‘It’s a listening post. Off-limits to Zephyr personnel. They don’t even know it’s here. Officially, it’s an offshoot of Menwith Hill.’

‘Menwith Hill?’

‘Yes. That’s an NSA operation, American personnel. The job is SIGINT, signals intelligence, picking up all sorts of information while it’s in transit.’ He gave a sly glance in Dreyfuss’ direction. ‘Nothing’s safe any more, not if it’s being transmitted. It still gets from A to B, of course.’

‘But on the way it’s listened to?’

Fagin slapped one of the machines proudly. ‘And copied. You name it: telephone conversations, rocket telemetry. Here, take a listen.’ He flipped a switch and a stream of noise started issuing from the speakers set into the walls. ‘Know what that is?’ he asked, his face opening into a smirk. ‘Computers talking to one another. Satellite computers.’ He pointed earthwards. ‘The ground asks Zephyr for close-ups of RAF Buchan.’ His finger jerked skywards. ‘Zephyr transmits this request to the other satellite, which then sends it live shots of a base in Wales, made to look like Buchan.’ He pointed downwards again. ‘Zephyr then sends these pictures to the ground. It’s quite easy if you think about it.’

‘You’re forgetting, Fagin,’ interrupted Villiers, ‘Major Dreyfuss doesn’t need to think about it. He was there when the satellite was launched.’

‘And when the crew were murdered,’ said Dreyfuss coldly. Villiers just shrugged.

‘A US branch decision. What could we do?’

‘I’ll tell you what you did do, though,’ said Dreyfuss, remembering Hepton’s story. ‘You killed a man called Paul Vincent, you tried to murder Martin Hepton, you murdered Cam Devereux, and God knows, that may only be the tip of the dagger.’

Villiers shrugged again but seemed, if anything, pleased by Dreyfuss’ catalogue. He glanced at one of four clocks on the wall, each one set for a different time zone.

‘Harry should have disposed of Mr Hepton by now.’

On hearing this, Jilly screamed behind her gag, her face purple with effort. Villiers was delighted by this effect and lifted his head to laugh. But a choking sound from Fagin cut him off.

‘What is it?’ he asked.