The head of the French column hesitated as the three allied battalions appeared over the crest of the ridge, halted, and then lowered their muskets to deliver the first volley of the battle. With a crash that carried clearly along the ridge to Arthur, the brigade struck down the leading ranks of the attacking column, leaving bodies heaped and writhing along the front. Then the guns on each flank blasted out. Grapeshot swept through the densely packed ranks, cutting down scores of men as heavy lead balls smashed their way through flesh and bone.

Despite this savage punishment the French soldiers in the rear ranks edged forward as sergeants and officers desperately ordered them to form line. Under fire from three battalions and the cannon, there was little chance of the change in formation being carried out with any sense of order. Instead, those at the front continued to fire and load as quickly as possible, shooting blind into the bank of gunpowder smoke that hung in the air between the two sides.

‘Those fellows are made of sterner stuff than most of the Frenchmen I’ve seen in action,’ Arthur commented. ‘By God, they can take everything that Mackinnon’s brigade are giving them.’

‘Aye, sir.’ Somerset nodded. ‘They’re bearing up to it, for the present. But they’ll break, soon enough.’ He paused, then squinted at the slope, closer to their position, before thrusting his arm out. ‘Sir, look there! Another column, I think.’

Arthur’s gaze followed the direction indicated and he saw the enemy, a screen of skirmishers emerging from the mist. They were headed up at an angle from their comrades, following a shallow gully up towards the crest of the ridge, halfway between Mackinnon’s brigade and the track leading towards Busaco convent. A quick glance told him all he needed to know.

‘There’s no one to turn them back if they don’t change direction.’

Somerset glanced at the crest, and saw that there was no sign of any allied officers to indicate the presence of their men on the reverse slope. ‘You’re right, sir.’

‘There isn’t much time.’ Arthur turned away from the wall and hurried towards the orderly holding the horses. With a lithe step up into the stirrup he swung his leg over the saddle. Somerset scrambled after him as Arthur spurred his horse into a gallop. They headed out of Sula and made their way along the crude road that had been cleared along the ridge by Arthur’s engineers. As they rode, Arthur kept glancing to his left to keep track of the approaching column. No doubt Masséna had sent both columns forward to take the crest, but they had become separated in the mist, and had continued up the slope in widely diverging directions. Now, by sheer bad luck, the second column was heading for an undefended stretch of the ridge.