Hepton, used to technical labs, nodded, impressed. There was hardware aplenty: computers, monitors, video cameras, recorders, a huge studio-style machine for editing and splicing film, projectors, and workbenches covered in all manner of electrical instruments, bits of chopped film, broken-open cassette cases. The place was a mess, evidence that a lot of work was done here.

‘All this Russian-doll stuff, a box within a box within a box, it’s really to cut down vibration from outside more than anything,’ Izzard explained. He bounced on the floor in his Dr Martens shoes. ‘Decoupled from the rest of the building,’ he said proudly. ‘That was my design, actually.’

‘This is incredible,’ said Hepton. He had been attracted to the computers, and stood over one now. He frowned. ‘I don’t recognise—’

‘That’s my design, too,’ said Izzard, running a finger over the keyboard. ‘We do our own software and, in this case, hardware. It’s just a number-cruncher, really. Do you know about computers?’

‘I work in a tracking station,’ said Hepton.

Izzard looked impressed and pleased. His face became more boyish than ever. ‘You track satellites?’ Hepton nodded. ‘I love all that stuff. Signals intelligence, comms intelligence.’

‘That’s what’s on these tapes,’ said Hepton, brandishing the bag. Izzard looked like a child offered sweets.

‘Yes?’ he said, reaching out a hand. ‘Well then, let’s put them on the machine and take a look.’ His tone became more serious. ‘What is it that you want exactly?’

‘I want to examine the pictures,’ Hepton said, following Izzard to one of the benches. ‘Side by side if possible.’

‘Very possible.’

‘And then maybe concentrate on a few shots.’

‘I can put them side by side on the same screen.’ Izzard turned to him. ‘If you like.’ Hepton smiled and nodded.

Izzard brought the tapes out of the bag. There was a note inside one of the boxes. You owe me a beer, Vic! He handed it to Hepton, then turned his attention to the tapes themselves.

‘Hmm,’ he said. ‘High-resolution tape, and plenty of it.’ Even Hepton could see that there was a good deal of tape on each spool: perhaps as much as a couple of hours’ worth. Yes, he owed Nick Christopher a beer.

He noticed that he had rested his hand on a small modem. He tapped it.

‘Ever done any hacking?’ he asked.

Izzard’s face lit up again. ‘Yes, years ago. I used to love it. What about you?’

‘I’ve done a little.’

‘I got into a couple of big companies’ systems,’ Izzard said, warming to his tale. ‘Left messages there for the staff. Stuff like: “Do you know what your wife’s up to right this second?” Childish, but still a lot of fun.’

Hepton smiled. ‘Wasn’t it difficult working out the code words?’

‘Hellish difficult, yes.’ Izzard had put down the tapes. ‘Typing in everything from aardvark to zygote.’