Moments later, with Ben at the wheel, they were racing off in the direction of the sound – or as directly towards it as the wildness of the undulating landscape would allow, with impassable drops, rockfalls, gorges and crevasses blocking their way at every turn, making it physically impossible to travel as the crow flies. The moon was bright enough to travel with no lights and they were moving upwind, so that with any luck their approach wouldn’t be detected. Judging from what they could hear, the incident was taking place no more than about quarter of a mile away, but the winding roundabout route Ben was forced to take, stopping frequently to listen and adjust their course, was frustratingly longer. Ben was afraid that the fighting might suddenly come to a stop, one side or the other having won, and they wouldn’t find them.

‘What the hell’s going on, Ben?’ Wolf asked tensely beside him in the dark, jolting cab.

Ben was just as baffled as the rest. Except for Operation Hydra, the last British army unit was supposed to have been pulled out of Afghanistan long ago, before the American troop withdrawal. Had Carstairs been playing some double game? He replied, ‘I don’t know, Jaden, but with any luck we’re about to find out.’

And they soon did. The rattle of automatic weapons much closer now, and sharp in the night air, Ben halted the Humvee at the bottom of a steep rise. The sounds were coming from beyond the ridge, carried up by the wind from the sharply sloping river gorge down below. Grabbing their kit, all five of them jumped silently from the vehicle. Communicating with signals they crept to the top of the rise and flattened themselves out among the rocks, peering cautiously over the edge into the moonlit gorge below. The rocks made long, inky-black shadows that obscured the deeper nooks and crevices down there, but with their powerful light-gathering binoculars they could see almost everything that was happening.

‘Well I’ll be damned,’ Holt muttered.

Sure enough, as baffling and unexpected as it was, their guess had been right. Some two hundred yards away in the twisting, dry river bed at the bottom of the gorge, a small unit of combatants in what appeared to be a rag-tag mixture of British multi-terrain pattern combat uniform and native desert garb were pinned down behind rocky cover by a much superior force of robed and mostly turbaned fighters spread out on the opposite slope above them. Dark figures flitted among the crags as the Taliban fighters steadily encroached on their opponents’ position, with the clear aim of working their way down into the gorge and encircling them before moving in for a final, decisive assault. Here and there the strobing yellow-white muzzle flash of automatic weapons appeared from the shadows, spewing bullets at anything that moved in a random cacophony of gunfire.