Shepherd reached for the door handle and pulled open the door. He caught a glimpse of a revolver and stepped back, dropping his clipboard and reaching inside his fluorescent jacket. He heard Crazy Boy shout something but all Shepherd’s attention was focused on the man in the cab and the gun in his hand. He grabbed the butt of the Glock and pulled it out and fired twice just as Two Knives was swinging his weapon up. Both rounds caught Two Knives in the neck, just under the chin, and he fell back as blood sprayed across the dashboard.

Shepherd turned just in time to see Crazy Boy reaching inside his overalls. ‘Stay where you are!’ screamed Shepherd. ‘Let me see your hands!’

Crazy Boy stared at Shepherd with undisguised hatred, froze for a fraction of a second, and then started to pull out a gun. Shepherd shot him twice in the chest and Crazy Boy fell back on to the grass, shuddered once and lay still.

Shepherd took a deep breath, then holstered his gun. He walked back to the police car. Traffic was continuing to drive by; the truck had shielded the killings from view and he doubted that anyone had seen what had happened.

As he reached the car his mobile phone rang. It was Major Gannon. ‘Can you talk?’

Shepherd walked away from the car. ‘Sure.’

‘You done there with your secret squirrel stuff?’

‘All taken care of,’ said Shepherd. ‘I’ll fill you in when I get back.’

‘I’d rather that was sooner than later,’ said the Major.

‘Is something wrong?’

‘I need to see you in Hereford, now.’

‘What’s happened?’

‘It needs a face-to-face, Spider. I’m sending a chopper.’

‘I’m miles away from Battersea,’ said Shepherd. ‘On the M25.’

‘I know exactly where you are,’ said the Major. ‘I took the liberty of using your GPS. The chopper’s on its way to you.’

Shepherd heard the whop-whop-whop of a helicopter in the distance. He squinted up at the sky. It was a Eurocopter Dauphin. ‘It’s here,’ said Shepherd.

‘See you soon, then.’ The line went dead.

‘Spider, are you OK?’ asked Button in his ear. Shepherd removed the earpiece and the radio and gave them to the driver of the traffic car, along with his fluorescent jacket, then he walked over to the field adjacent to the hard shoulder to wait for the helicopter.

The Dauphin did a slow circle around the Stirling Lines camp and then came in to land a short distance from a bright orange windsock that was hanging limply from a pole. Shepherd jogged away from the helicopter, bending low as the rotor continued to turn above his head.

The Major walked over from the main administration building. He was wearing a dark green T-shirt and camouflage pants, his face set like stone. He was holding a manila envelope. ‘What’s happened, boss?’ asked Shepherd.