Napoleon was furious, and immediately sent an order for Ney to report to him at headquarters. Two days later Ney arrived, soaked through, spattered with mud and exhausted after a hard ride from Tudela. He was ushered into the imperial presence immediately and stood to attention under the glowering eyes of the Emperor as rain beat against the windows of the office.

‘You have let me down, Ney,’ Napoleon began.‘What is wrong with my commanders that they should fail me so? First Victor underestimates his enemy and leaves his corps strung out and vulnerable to counter-attack. I ask you, how could a man of his experience underestimate the worst army in Europe? Then Lefebvre sends his men in piecemeal attacks against entrenched troops. And now you do not arrive in time at Tudela and the enemy escapes. Tell me, Ney, what is your excuse this time?’

‘This time?’ Ney replied with evident ill-temper. ‘And when have I let your majesty down in the past?’

‘The past does not matter.’ Napoleon dismissed the comment with a curt wave. ‘You failed to move your army quickly enough. Because of you most of the enemy escaped.’

‘Sire, you asked the impossible. When your orders reached me I was required to lead my corps one hundred and twenty miles in three days. Over mountains. It was impossible. No soldiers in the entire army could have done that.’

‘It might have been possible had you not rested your men for two days at Soria.’

‘It was barely a day, sire. Half the men were straggling. I had to let them catch up or I would not have reached Lannes with enough men to serve any purpose.’

‘Rubbish! Davout managed an equally hard march before the Battle of Rivoli.’

‘Sire, that was half the distance, over better roads,’ Ney protested.

‘You dissemble, Marshal Ney, and you know it.’ Napoleon thrust a finger at him. ‘Admit it, you failed to do your duty.’

‘No, sire. I did my duty.’ Ney’s expression hardened.‘What I failed to do was the impossible. If you had considered the matter more closely before you sent me my orders you would surely have seen that.’

Napoleon breathed in sharply. ‘How dare you speak to me in such a manner!’

But Ney was not cowed and nodded towards the wall. ‘Look at the map if you don’t believe me. Measure out the distance with those dividers you are so fond of. Then you’ll see I speak the truth.’ Ney paused a moment to control his rising temper. ‘Sire, I serve you loyally. I am a soldier and I obey orders to the utmost of my ability. But if the orders are at fault then I will not take the blame for the consequences. Now, if you feel I have betrayed your confidence, or, indeed, you feel no confidence in my abilities, then dismiss me. I will not be held to account for the failings of another.’ Ney stiffened to attention. ‘Sire.’

There was silence as the two men glared at each other. The only noise was the rain at the window and occasional dull whirr as a gust of wind swept round the building. Napoleon gritted his teeth. He was enraged by Ney’s defiance and for a while he was almost consumed by the desire to dismiss the marshal on the spot and send him back to France in disgrace. But he was forced to admit that Ney was a fine leader, and a capable subordinate. He had served his country bravely and loyally and been promoted to his present rank by Napoleon himself. Ney was a popular man, both within the army and with the French public. If Napoleon dismissed him now, his own judgement might well be called into question. That would not do. The latest reports from Fouché indicated that the people were becoming increasingly disillusioned with the almost perpetual state of war. Open dissent between the Emperor and his marshals would only increase unrest.

Napoleon relaxed his jaw.‘Very well then, Marshal Ney. I accept your explanation. This time. But do not fail me again.’

‘I did not fail you this time, sire,’ Ney replied gruffly.

Napoleon lowered his hands below the desk, out of sight, as he clenched them so tightly that every drop of blood drained from his knuckles. ‘You were not where I wanted you to be, and the enemy escaped. However, on reflection, I will not hold you wholly responsible for that.You are dismissed. Return to your corps at once.’

‘At once?’ Ney glanced wearily towards the rain-streaked window and sighed.Then he bowed stiffly to the Emperor and turned to march out of the room, closing the door forcefully behind him.

Napoleon stared at the door for a moment. Then he picked up his dividers and walked across to the map. He adjusted the instrument to fit the scale and measured off the distance that Ney’s corps had been ordered to march. The dividers passed over territory marked as mountainous and broken by many streams and tributaries. For long stretches there were no roads marked on the map. It was, as Ney had said, roughly a hundred and twenty miles. A fresh division of infantry might have encompassed it, Napoleon told himself, but a whole army corps, burdened by its wagons and artillery, could never hope to march such a distance in three days.

Why had he not seen this? It was a lapse of judgement. He would not have made such an error ten years ago, or even five.Was age making his mind less acute? He dismissed the thought. He was not yet forty, surely not old enough for that. But what if his judgement was at fault? What if the organisational brilliance that had made him the master of Europe had become corrupted by his success? It would not be the first time that a great man had fallen prey to the temptation to view every decision he made as infallible.The prospect appalled him. For a moment Napoleon was furious with himself for not making the correct allowances for Ney’s movement.Then he forced the very idea of it from his mind. It could not be his fault.

In fact, he recalled that he had given the order without consulting the map. It had been a hectic night when he had dictated his plans to Berthier. Why had Berthier not mentioned the difficulties that Ney would face in keeping to the allotted time for his advance? It was Berthier who had failed him, not Ney. He decided that he must pay closer attention to Berthier from now on. Perhaps the man was growing too old, too weary, to carry the burden of being the Emperor’s chief of staff. Berthier would have to be watched to ensure that he did not make any more such mistakes, Napoleon told himself sadly. Berthier was a good man, but he had let his Emperor down and caused him to blame wrongly a fine officer like Ney. Well, Napoleon comforted himself, his subordinates were only human. Once the campaign was over he would have a word with Berthier and suggest that the chief of staff apologise to Ney for making him the target of Napoleon’s anger.

There was a knock at the door, and Berthier entered. Napoleon stared at him for a moment, uncertain whether to be angry with the man for causing the earlier scene, or to feel pity for Berthier’s mortal failings. In the end he opted for the latter, and smiled condescendingly.

‘What is it?’

‘A report from one of our light cavalry regiments, sire. They have been scouting along the River Duero and have discovered that the British are on the march.’ Berthier crossed to the map and tapped it. ‘They are heading in the direction of Salamanca.’