His thoughts were interrupted as the French unleashed their first volley at the approaching redcoats. All along the front of the approaching line men staggered or fell to the ground under the hail of musket balls. Their sergeants bellowed the order to close up and the leading formations advanced another ten paces and halted, leaving a scattered band of red figures, dead and injured, in their wake. The British managed to fire their first volley an instant before the French replied with their second and a thick pall of smoke billowed between the two sides as hundreds of men were struck down. The soldiers of both sides reloaded and fired as quickly as possible, ignoring the cries of their stricken comrades and the sprawled bodies of the dead on either side.

After the fifth volley, the order was given to charge and the British surged forward, momentarily disappearing into the smoke before bursting out the other side, straight at the startled French. Arthur watched the two lines clash, the leading ranks merging into a bloody, merciless mêlée as the men fought hand to hand. More redcoats surged through the slowly dissipating cloud of powder smoke and the French began to give ground. The British pressed on, and then, as if caught by some herd instinct, the enemy broke and ran, streaming back across the open ground towards Vitoria.

Arthur turned to look expectantly towards the waiting cavalry. Unlike his previous battles in the Peninsula, when lack of cavalry had removed any chance of a successful pursuit, this time his mounted arm was a force to be reckoned with. Five cavalry brigades, nearly six thousand men, stood ready to be unleashed. As the French began to flee the regiments began to walk forward. The rear formations of the infantry line opened up to let the horsemen pass through and then the cavalry spread out again, picking their way over the bodies of those who had fallen in the exchange of fire shortly before. As the leading formations of the infantry saw the cavalry approach they hurriedly clustered together to avoid being trampled. The riders continued to advance at the walk until they had cleared most of their comrades in the infantry. Then the bugles sounded, the rising notes sounding thin and tinny from where Arthur watched the magnificent drama as they increased the pace from walk into trot, and then the canter, and finally the gallop as their riders spurred their mounts on and advanced their sabres with a throaty roar that drowned out the sound of the bugles.