Half an hour later, the signal gun announced the opening of the battle, and the French batteries thundered out. At first they concentrated their fire on the defenders in the villages along the bank of the river, and then, as the order was given for the infantry to advance, they shifted their aim to begin wreaking terrible destruction in the ranks of the Prussian reserves drawn up in full view on the slope behind the stream. Roundshot smashed into the formations, leaving a trail of bodies and limbs to mark their passage. Despite the losses, the iron discipline of the Prussians held up, and the battered battalions closed up the gaps and stood firm.

Through his telescope Napoleon watched the progress of the attacks across the stream as his men fought to gain control of the villages covering the bridges and fords. The enemy fire was withering and the soldiers following the tricolours were being scythed down as they advanced. Yet their morale never faltered and the cheers for their country and their Emperor carried back faintly but clearly to Napoleon as he watched the bloody struggle.

Soult was at Napoleon’s side and muttered, ‘Our men are taking heavy punishment, sire.’

‘As are the enemy,’ Napoleon replied. ‘We just need Blücher to commit his full strength to the fight, and the Guard and Ney will deal the decisive blows.’ Napoleon lowered his telescope and focused his mind on the surrounding landscape once again. It would be as well to spur Ney on, to ensure that his men reached the battlefield in time to strike as hard a blow to the enemy as possible.

He turned to Soult. ‘Send a message to Ney. Tell him the battle is in full swing. He is to manoeuvre immediately in such a way as to envelop Blücher’s right and fall upon his rear. Tell him the fate of France is in his hands.’

Soult nodded as he finished scribbling down the message in his notebook and then hurried over to his aides to have the note rewritten in a fair hand. A moment later a despatch rider spurred his horse into a gallop and headed west towards Quatre Bras. Napoleon turned his attention back to the vicious struggle along the banks of the stream and noted with satisfaction that the first of the villages had fallen into French hands as a tricolour appeared in the tower of the church.

‘Sire!’ Soult called out as he trotted over from where his staff sat hunched over their campaign desks, dealing with the constant flow of reports and orders. He held up a scrap of paper. ‘From Ney.’

‘Well?’

‘He reports that he is engaging Wellington at Quatre Bras. He estimates their number at twenty thousand, with more sighted approaching the crossroads.’