‘We dare not take the whole army across the river using a single span. It would take too long, and if the enemy can bring forward sufficient strength to attack the bridgehead then we could be stuck here while Kutusov approaches from the east.’

‘That is a possibility, sire,’ Berthier agreed. ‘But if the ground on the far side is held by a few bands of Cossacks and the remnants of the column that Eugène forced aside, then I would say it is worth the risk. If the army gets over the Lusha then there are few natural obstacles between us and Smolensk.’

Napoleon thought a moment and then shook his head. ‘It would take only a few cannon to sweep the bridge and there would be a panic. We would lose thousands - men I cannot afford to lose. No, the army cannot cross here.’ Napoleon traced his finger across the map. ‘We’ll head north, back to the Moscow-Smolensk road.’

Berthier sucked in a breath. ‘But that will cost us six days, sire. We can’t afford to lose so much time.’

‘Time is irrelevant if there is no army left to make use of it.’ Napoleon straightened up and rubbed his back. Even though he had slept little in recent days he felt something of his old energy returning. His stomach was no longer hurting, he realised.

He continued to stare at the map. It was possible that Berthier was right, he conceded silently, and the march north would cost him six days, but the danger of attempting to cross the Lusha outweighed Berthier’s fears.

A sudden gust of wind caused the map to flap where it wasn’t clipped to the table. Napoleon shuddered and turned to one of the orderlies waiting outside the carriage. ‘Find me a warm coat.’

Several days later, the army re-joined the road to Smolensk and passed through the battlefield at Borodino. There had been no time to bury the vast number of dead men and horses when the Grand Army had pursued Kutusov in the direction of Moscow after the battle six weeks before. Since then the corpses had swollen, putrefied and been scavenged by packs of wolves that had been drawn from many miles around by the scent of death. Amid the ravaged bodies was the litter of war: abandoned muskets, shattered gun carriages, cavalry helmets and breastplates, cleaved by musket and cannon fire.

‘Good God . . .’ Berthier muttered as he gazed around the desolate landscape as the headquarters column passed through. He sat opposite Napoleon in an open carriage.

‘An ugly scene,’ Napoleon nodded, and then wrinkled his nose.‘And a foul stench, even now.’