Grimm waved the pass in front of him. ‘You can give me a lift towards Peronne. This pass says you must give me any help I need.’

The driver smirked. ‘That pass might say you’re a clown looking for a custard pie in the face... I wouldn’t know. I can’t read... sir.’

Grimm pulled himself into the passenger seat and said, ‘Drive.’

‘I’m not going as far as Peronne... sir.’

The sergeant shrugged. ‘I’m not going all the way by road. It would take too long. There’s a quicker way.’

The driver crunched the gear lever into place and set off. ‘Not on these roads there isn’t. They’re packed. You’ll only go as fast as the horse-drawn guns.’

Grimm’s thin lips turned down in a sort of smile. ‘Not me, driver. Take me to the nearest airfield. There’s one down by the Somme, isn’t there?’

‘Ah yes, sir. It used to be Baron von Richthofen’s airfield, they reckon. He’s gone now, of course. Have you ever flown in one of those planes? Wood and wire in the wind. You’d never get me up in one of them. Lord, no...’

‘Driver.’

‘Yes, sir?’

‘Shut up and drive.’

The rain began to fall and drummed on the roof of the cab so loud that Sergeant Grimm couldn’t hear the swear words the driver muttered.

26 August 1918: The Somme airfield

Sergeant Grimm ordered his driver, ‘Stop here,’ as they reached the gate to the airfield. Rain was streaming down from clouds that were rooftop low. Mechanics were throwing covers over the engines and cockpits of the planes that stood on the grass runways. The Germans had wrecked the tin-roofed sheds before they abandoned the airfield and flew east.

The lorry skidded to a stop. Grimm opened the door and jumped down into the puddled road without a ‘Thank you’ to the driver. He showed his pass to the miserable, dripping guard at the gate who pointed to a wooden hut fifty yards away by the fence. ‘You need to see Flight Commander Jackson, sir,’ he said.

Silver Hand hefted his pack on to his back and bent his head against the driving rain. His boots splashed over the wet grass and he trotted to the hut. He knocked sharply and was told to enter.

He stood at the door and shook off the rain. The commander was a sour-faced, thin man with a deep red scar on his left cheek. ‘Army, eh?’ he said, looking at Grimm. ‘What does the army want with us? More orders for ground support I suppose, eh? Well let me tell you, Sergeant, flying low over the enemy and shooting at soldiers is a dangerous job. We lost two good fighter pilots only yesterday. The German machine guns are waiting for us.’

‘No, sir...’