Then Arthur dismissed his opponent from his mind as he scrutinised the scene before him. The arrival of Aylmer’s brigade had put fresh heart into the Portuguese troops, who had been fighting valiantly all morning but had been close to being overwhelmed. Now they closed up in front of their colours and braced themselves for another French onslaught. The enemy infantry had moved aside to make way for a brigade of cavalry: dragoons, in heavy coats with flowing crests atop their gleaming helmets. They walked their horses forward and slowly spread out across the muddy ground in front of the ridge. Arthur was relieved to see no sign of the enemy’s guns, no doubt still stuck in the mud beyond Barroilhet.

‘Not the best conditions for cavalry,’ Hope commented.

‘And no need for your men to form square,’ Arthur responded. ‘I doubt that those dragoons will make any speed over that mud. A few volleys will see them off long before they pose any danger to our line.’

Hope stared at the ground and nodded before turning to one of his staff officers. ‘Campbell, ride down our line. Tell the colonels that their men are to remain where they stand.’

The officer saluted and then spurred his horse away to relay the order.

It took over half an hour for the French cavalry to deploy, and when at last the advance was sounded the heavy mounts struggled through the mud as they picked their way towards the bottom of the slope.

‘What I’d give for a battery of nine-pounders,’ Hope commented bitterly. ‘Case shot would make short work of ’em.’

Arthur turned his gaze away from the dragoons towards the nearest of his men. They stood their ground and waited, with not a backward glance. As Arthur had expected, the poor ground slowed the cavalry to a walk, and they were still moving no faster when the order to make ready to fire echoed along the allied line. The muskets were advanced, and then there was a brief pause before the order to cock the weapons was bellowed and a light clatter filled the air.

‘Take aim!’

Up came the muskets, and each man pulled the butt in tight against his shoulder, anticipating the savage kick as his weapon was discharged. Arthur saw that the dragoons were perhaps seventy or eighty yards away. A longer range than he would like, but the large targets would be easy enough to hit when the volley was unleashed.

‘Fire!’

The volleys of each company of British and Portuguese troops crashed out along the line, spitting over a thousand musket ball into the oncoming formation.

‘Reload!’ a sergeant cried out. ‘Reload your weapons, blast yer!’