Before Arthur could reply the sound of a cannon ball passing close by filled the air with its drone, and he felt Uxbridge’s fingers suddenly dig into his sleeve.

‘I’m hit . . .’ Uxbridge looked at him, wide-eyed. ‘I’m hit.’

Arthur reached over and grabbed his shoulder to steady him. ‘You there!’ he called to a gun crew who had retreated to Maitland’s brigade. ‘Help me. Get this officer to the rear!’

The gunners eased Uxbridge down from his saddle and laid him on the ground. Arthur saw that his knee had been smashed by a roundshot and was now a bloody mess of bone and muscle. The artillery crew picked him up and Uxbridge let out a deep groan as they moved off. Arthur turned back towards the battle and looked down the slope. There were still four battalions of guardsmen formed up, but they were now slowly falling back, covering the retreat of their stricken comrades. Over to the right, the garrison of Hougoumont still held on as they fought to contain the fire that had broken out earlier. To the left, the French were abandoning La Haye Sainte and retreating down the road to Charleroi. Over to the east Arthur could clearly see the columns of Prussians pushing back the remnants of the Young Guard.

‘By God,’ he muttered to himself. ‘We’ve done it . . . We’ve won.’

Somerset came riding up, his face alight with excitement. ‘Your grace, d’you see? The French are broken. They’re retreating!’

Arthur could not restrain himself a moment longer. The strain and anxiety of the terrible contest was lifted from him and he felt a wave of elation course through his body. Somerset was grinning at him.

‘What are your orders, your grace?’

Arthur took off his hat and waved it above his head, in the direction of the enemy. ‘Give the order to every man you can find - general pursuit.’