Despite his dismissal of Somerset’s concerns, Arthur accepted that there were risks. He had marched the men hard, and they were weary and might yet go hungry for a short time, but what Somerset seemed to have missed was the desire to close with and destroy the French that simmered in their breasts. They had resented the loss of the second chance to fight the enemy at Salamanca, and now were set on crushing them.

During the night, the army was woken by the sound of a great explosion rumbling across the landscape. Shortly afterwards there was a red glow in the sky to the east that shimmered against the scattered clouds drifting across the starry heavens. Arthur watched from outside his tent, barefoot and dressed in breeches and a loose shirt. The glow continued for two hours before it began to fade, lost against the first hues of the dawn. Arthur returned to his tent to get fully dressed and was just emerging when Somerset reported to him.

‘It was Burgos, my lord. One of the cavalry vedettes was close enough to see the explosion.’

‘Explosion?’

‘Yes, sir. The French set charges and blew the castle to pieces. They managed to burn down a sizeable portion of the town while they were at it.’

‘Well, bless my soul,’ Arthur muttered in surprise. The French were clearly panicking more than he had thought. That in turn introduced a new anxiety. What if the enemy’s experience of the previous years had so cowed their spirit that they dared not stand and fight? If that was the case then Arthur’s plan had to be adapted so that when the chance of battle came there would be no avenue of escape for the French. Joseph and his army would have to be caught in such a way that they would be forced to surrender, or be annihilated.

The leading division of the allied army quit the barren hills two days later and entered the Ebro valley. The change in the landscape was striking and for the soldiers, so used to tramping across the dusty, dry plains and hills of central Spain, the lush valley watered by the river was a vision of abundance. The roads along which the army marched were lined with fruit trees and vineyards and the soldiers, when their officers were not looking, filled their haversacks with cherries, oranges and apples to supplement their dwindling rations. They continued a short distance to the east before turning south towards the crossroads at San Millan.

Late in the afternoon an excited young lieutenant from the Ninety-fifth Rifles galloped up to Arthur with a message from General Alten. ‘My lord! We’ve sighted the enemy!’

‘Lieutenant, that will not do,’ Arthur admonished him. ‘Start again and deliver the message properly.’