‘Any report of other enemy columns in the area? Or anywhere on the Portugal road?’

‘No, sir.’ Somerset had rarely detected such anxiety in his commander’s voice and added, reassuringly, ‘I am certain of it. I read all the reports first thing this morning. This is the only French army near Salamanca.’

‘And you would wager your life on that?’ Arthur asked curtly.

‘I would.’

Arthur turned to look at his aide, his eyes filled with contempt. ‘Then you are a fool, Somerset. Or a charlatan.’

Somerset swallowed his anger. Wellington was not himself and allowances had to be made, so he held his tongue as the general turned his attention back to the enemy, the fingers of his left hand tapping out an unconscious rhythm on his saddle holster. Arthur had a clear view of the enemy commanders and their staffs, crowded about the same position Marmont had occupied in the earlier battle. Raising his telescope, he trained it on the large group of horsemen and picked out the elaborate uniforms of Joseph and his senior commanders. They seemed to be locked in an animated debate.

As Arthur watched them he heard a faint pat on the brim of his hat, then another. Lowering his telescope, he saw that it had begun to rain. The pattering became more general, and then merged into a hiss as the rain fell in earnest, creating a steely veil between the two armies. Arthur glanced up at the sky and saw that the clouds had spread to the horizon. The most distant hills had already been blotted out and those only a few miles off had been reduced to grey outlines.

‘Still no movement from the enemy,’ an officer muttered.

Arthur nodded, and thrust his telescope back into the saddle bucket, fastened the buttons of his cloak, and sat stiffly as he considered his next move. The rain would handicap both sides. The French would have to advance across the muddy floor of the valley before mounting the slope leading up to the allied position. Infantry and cavalry alike would be hampered by the soft ground. At the same time, the rain would increase the number of misfires from Arthur’s men, which would reduce the firepower of his line, a worrying factor given that he was already outnumbered. As he was thinking, Somerset rose up in his stirrups and pointed towards the far ridge.

‘Sir, look there. The French are on the move.’

Arthur raised a hand to shield his eyes from the rain and squinted. Sure enough, the men of the enemy cavalry reserve, massed on the crest of the ridge, were mounting their horses. Then, one squadron at a time, they turned and rode away over the ridge. As the order spread to the other formations, the French army began to withdraw towards their camp.

‘It would seem that rain has stopped play,’ Somerset said.