‘The suggestion is that, once you’ve got Apple in position, you should block the tunnel on the river side of it by dropping the roof, as if there had been a natural fall.’

‘Not that easy if it’s concrete.’

‘I didn’t say it was concrete.’ A hint of irritation edged into the Scot voice. ‘The tunnel is lined with brick, and it’s not in the best of condition.’

I nodded in token condition.’

‘Even if you do drop the roof, it is recommended that you brick the device into the tunnel wall.’

‘Hard to camouflage new mortar.’

‘That’ll be up to you. I imagine there may be dust or mud that you can smear around.’

Next Whinger came up with, ‘How do we get the devices on site?’

The CO looked at Laidlaw, as if asking permission to intervene, and said, ‘They’ll travel out with you on the Here, sealed in Lacon boxes. They can be marked the same as ammunition. The weight will be about right. At the other end it’ll be up to you to devise ways of moving them to their final positions.’

‘What if the Here goes down with the devices on board?’ asked Pavarotti. ‘What’s the chance of a premature detonation?’

‘None,’ said Laidlaw. ‘Even when the two halves of each device are united, nothing can happen until the control box has been interrogated and primed by satellite signal. You need have no worries on that score.’

Thanks, I thought, feeling crushed with a sudden terrific weight of responsibility. The boss was going on again about the paramount need for security; but although I could hear what he was saying I was wondering how the hell I could carry out the training mission with this knowledge in my mind. Every day we’d be dealing man-to-man with our students, instructing and encouraging them, and at the same time, behind their backs, we’d be plotting to annihilate them.

As the main briefing was coming to an end, the CO drew me aside and said, ‘One thing to remember, Geordie: whatever happens, don’t let yourselves get involved in any live operation, like you did in Colombia.’

‘That was different, Boss,’ I protested. ‘When Peter lifted, we had to do something about it.’

‘I know. But what I’m saying is that we don’t want any repetition. Even if the Russians beg you to take on a job for them, refuse.’

‘Will do.’

From the briefing we went into a close-up study of the two sites. Laidlaw produced large-scale drawings with much detail on them.

‘All this information is on compact discs, which you can obviously take with you,’ he said. ‘The discs are programmed so that if anyone tries to get into one without using the correct password, the contents are automatically destroyed. Nevertheless, you obviously want to handle the discs with the greatest care.’