By the entrance to the aircraft hangar where they had first arrived was the spook who had briefed them. He showed no signs of having been up all night. His clothes, despite the already uncomfortable heat, were neat. There were no bags under his eyes. He addressed Sam, because Sam was the first to arrive at the hangar.

‘Care to tell me what the hell went on out there?’

Sam stopped. He turned slowly to look at the man.

‘What?’

‘I said, care to tell me what the hell went on out there?’

Stay calm, Sam told himself. He could feel his blood like lava under his skin. ‘I thought,’ he replied as mildly as he was able, ‘that perhaps you could tell us that. There was a waiting party for us. Russian special forces. A bit of an intelligence fuck-up – I’d say it was you that’s got the explaining to do.’

A voice from behind. Mac. Quiet. ‘Take it easy, Sam.’

But the spook spoke over him. ‘Listen to me, soldier…’

Something snapped in Sam. Blinded by a sudden rage, he stepped towards the spook before he could even finish speaking, grabbing him by his collar and pushing him roughly against the wall. ‘No,’ he hissed. ‘You fucking well listen to me, sunshine…’ The spook weighed nothing; his square glasses fell from his face and his previous look of smug resolve had changed to one of alarm. Sam sneered at him, but as he held the guy up against the wall, the words just seemed to dissolve from his mind, leaving only the anger.

Hands on his shoulders, pulling him back. ‘Leave him, Sam.’ Mac’s voice. Not loud, but firm.

Time stood still. Sam felt the spook trembling. With a contemptuous flick of his hands he allowed the guy to fall. His knees buckled as he hit the ground, but he managed to stay standing. Back on terra firma, however, the anger returned to his face. He opened his mouth to deliver some sort of reprimand; but then Mac was there. Like a father hushing a small child, he put one finger to the spook’s lips. ‘Tell you what, pal,’ he said. ‘Do yourself a favour and shut the fuck up, okay?’

The spook looked at Mac, then at Sam, then at the half dozen other burly SAS men that had surrounded him. His face twitched.

‘Your flight back to Brize Norton leaves in half an hour.’

Mac nodded with satisfaction. ‘Good lad,’ he said, making no attempt to avoid being patronising. He turned to Sam. ‘Come on, mate,’ he said. ‘Let’s get ready.’

Sam looked down at the floor, suddenly embarrassed about the way he’d been with Mac. ‘All right,’ he mumbled.

They walked away together. But as they did, the spook called out from behind them, emboldened perhaps by the fact that they were leaving. ‘Don’t think that’s the end of it!’ he shouted. ‘You’ll pay for that!’ His voice sounded ridiculously poncy, like the bully in the playground of a posh school.

It just so happened that as the spook called out to them, Craven’s body was being wheeled off the Hercules. Sam turned back to the man, but this time he knew he could keep himself under control.

‘We already did,’ he spat. ‘We already did.’

And with that he turned, pleased to be leaving Bagram – and that nob-jockey spook – behind him.

He didn’t need a sleeping tablet to knock himself out on the return journey. None of the boys in the troop did. He simply hung his hammock on the other side of the plane to where Craven’s stretcher was attached and within minutes of being airborne he was asleep. A deep and dreamless sleep, despite the hum of the jet engines and the troubles of the night before.

It was around midday when they stepped out onto the tarmac of Brize Norton. The air was misty and damp – a thousand miles from the clear, dry heat of northern Afghanistan. With a sickening lurch, he saw a regular civilian ambulance parked close to the plane, its blue light flashing silently in the misty air, its rear doors open. That was for Craven; the rest of them were to be transported in the same two white buses that had brought them to the RAF base in the first place. Only this time, there was an addition.

At the foot of the steps leading from the aircraft, an MOD policeman stood counting them all off. He wore a white, open-necked shirt, black body armour and a protective helmet. In his fist there was a Heckler and Koch MP7. He didn’t look like he was there to welcome the lads back from holiday.

There were four more of them, all tooled up, all standing in such a formation as to encourage the men straight on to the buses. ‘What’s with the plate hangers?’ one of the guys asked the policeman at the bottom of the stairs as he passed. ‘Worried we’re going to run riot?’

The policeman remained expressionless. ‘Just move on to the bus,’ he ordered.

A silence among the men as they were herded by these armed police on to their transports, and not a happy one. As they took their seats, a discontented murmur arose. Sam and Mac sat together. They didn’t speak. They didn’t need to. They knew something was wrong. They watched through the window as Craven’s body was loaded into the ambulance, then driven out of sight at a funereal speed, the vehicle’s flashing light like some kind of beacon. But it wasn’t the only flashing light they’d be seeing. Once the doors of the buses were closed up, two black police vehicles arrived. Their windows were blacked out, but they, too, had the emergency lights blinking on top. The convoy pulled away, one MOD vehicle at the front, the other at the back.

‘Where are we going?’ one wag shouted from behind. ‘ Hereford or Wormwood bloody Scrubbs?’

A smatter of laughter. Sam didn’t join in; he glanced at Mac, who returned his look with a raised eyebrow. ‘I think our little secret might be out,’ he murmured quietly, so as not to be heard.

Sam looked out of the window. More British Army soldiers congregated glumly outside the main terminal building. The sight of the two white buses being escorted off the airfield supplied a welcome diversion for them: they stared as the squadron passed.

They were on the main road before Sam turned to Mac. ‘Thanks for your help back at Bagram,’ he said quietly. ‘That guy – I don’t know, he just got to me.’

‘Forget about it,’ Mac replied lightly. ‘I know what you Redmans are like when you see the red mist. Bunch of fucking lunatics. Thought you were going to do a J. on him.’

It was an inappropriate joke, but Sam smiled anyway. ‘Yeah,’ he replied. ‘We should probably try to chill a bit.’ He looked around to check nobody else was listening. ‘Look, mate, I don’t know what all this police stuff is about, but when we get back to base, deny everything, okay. This is my problem. I don’t want you taking the rap for it.’

Mac shrugged. ‘Whatever you say,’ he replied.

‘I mean it, Mac.’

‘Yeah,’ Mac replied. ‘I can tell. Look, Sam, I don’t know what’s going on. You don’t want to tell me, fine. But any time you need some extra muscle, you know where to come, right?’

Sam surveyed his friend. ‘Yeah,’ he replied brusquely. ‘Thanks.’

The gates to RAF Credenhill were already open when they arrived – clearly someone had radioed ahead to let them know they were on their way. When they came to a halt in the main courtyard the conversational buzz in Sam’s bus – which had fallen to a silence towards the end of the boring drive – started up again. Something was going on here. There were more police vehicles for a start, and quite a number of MOD officers all carrying their MP7s. One of them approached the back of the bus and opened it.

‘All right, you lot, out you get, but no moving from the courtyard.’

‘What the hell’s going on?’ It was Davenport and he sounded like he’d had enough.

‘You’ll find out soon enough. Come on, down you get.’

They de-bussed and started hanging around in groups. A few of the guys lit cigarettes. A lot of them grumbled. They were knackered. They just wanted to get back home and didn’t appreciate being treated like a bunch of jailbirds.