The pilot shouted over his shoulder, ‘Because if we land they will shoot us like ducks on a pond.’ He saw another Camel appear over the head of Marius and swerved. ‘Keep firing.’

Again the wild stream of lead sent the enemy diving away for safety.

The Baron looked around again. ‘Now we are not ducks on a pond. We are the decoy duck. While the British are shooting at our poor helpless little plane the rest of my squadron are climbing in the clouds like falcons waiting to swoop.’

There was a distant pattering rattle of machine guns and the Baron grinned. ‘And here they come,’ he said.

Marius swung round in his seat to see six coloured triplanes dive down on to the surprised Camels. They were a rainbow of death. They swooped and twisted like the falcons the Baron had promised. Marius watched, mouth open, and almost felt sorry for the British pilots.

The Camels turned towards the river and headed back west with the triplane hornets stinging them with bullets. One Camel was on fire, its engine spilling black plumes behind it, then it disappeared from his sight as the Baron brought their two-seater in to land gently on the grass and coast towards the village of tents on the edge of the airfield.

The engine stopped and steamed and crackled. The pilot climbed down and waited for Marius to join him on the ground, legs shaking and heart drumming. Mechanics ran towards the plane to lift the damaged tail-plane and pull it away to be repaired.

A tall man in a cap with a ghost-gaunt face strolled across. ‘Well done, Manfred. Did we get the balloon?’

‘No. This soldier spoiled my aim. The balloon went down but I don’t think I hit it.’

‘It didn’t have time to take pictures though?’

‘No, Commandant, but it will live to fly another day.’ He looked across the airfield towards the red triplane. ‘I’m off to hunt British turkeys, but first I will shoot this boy. Stand him in the middle of the field and I will use him as a target to warm up my guns.’

‘Manfred,’ the thin officer moaned. ‘You know you can’t do that.’

‘I am Manfred von Richthofen, Germany’s greatest hero of the skies. No one will dare to punish me.’

He strutted away to the red plane, which was ready to fly. ‘I’ve heard of him,’ Marius said. ‘The Red Baron, they call him. He really is our greatest hero. Will he shoot me?’

‘Only if you run.’ The pale officer sighed. ‘Stand in the middle of the field. He will fly towards you. Look him in the eye and he will admire your courage. Turn and run and he may do something nasty.’