For the next few days my most important task was to keep up the momentum of our countdown to departure; but at the same time I had to show Sasha round the base and give him an idea of how we did things. Certain areas of camp were out of bounds to him, notably the SAW and the ops room, but there was plenty else for him to see, not least the Killing House, where the CT team laid on a demonstration of hostage-lifting. At first he was cautious about expressing opinions, but the more time I spent with him the more he became prepared to criticise or compare our methods with his.

For us, Killing House demos were routine, but for Sasha they were an eye-opener. The guys put him and me into the left-hand corner of a special room, corralled with two other visitors behind white tape. As usual, the live hostage-figure was sitting on a chair in the middle of the room, with his two guards, in the form of figure-targets, on either side of him. Behind the hostage stood the sergeant in charge, commentating on events.

Just as he seemed to be in the middle of his spiel, giving the principles of close-quarter battle: ‘Speed, aggression, surpr—’ BANG! Loud explosion. Door blown off. Two assaulters running in. Ba-ba-bom! Ba-ba-bom! Short bursts from MP5s. Targets riddled, hostage lifted and gone before anyone else could react. Nothing left but smoke and dust.

As our ears recovered, Sasha turned to me, beaming, and said, ‘Vairy good! Vairy prafyessional!’

Before we went out he took a close look at the construction of the building, pulling back the metre-wide sheets of thick red rubber, which overlapped each other by nearly half their width, so that he could inspect the steel-plated wall some three inches behind them. Seeing all the crumpled bullets lying on the floor, he understood at once how the rubber caught anything which flew back off the wall, killing its energy.

‘This we would like,’ he said wistfully, looking round.

‘You don’t have it?’

He shook his head. ‘Only rubber wheels.’

‘Tyre houses?’

He nodded.

I knew what he meant, because I’d seen them in the States: skeleton buildings with walls made of piled-up motor-tyres filled with concrete, which, in a crude way, performed the same function as the rubber sheets.