Getting the rest of his forces ready for battle he kept them inside the camp, and sending off the velites and a picked force of foot he ordered them to throw themselves on the ridge and attack the enemy's covering force.
They executed his order with great gallantry, and at first the Carthaginian commander remained waiting for the result. But when he saw that, owing to the dashing courage of the Romans, his men were hard pressed and in an evil plight, he led out his forces and drew them up near the ridge, relying on the strength of the position.
Scipio at once dispatched the whole of his light-armed troops with orders to support the force which had commenced the attack, and having the rest of his army ready, he himself took one half of it and skirting the ridge to the left of the enemy fell upon the Carthaginians;
the other half he gave to Laelius with orders to attack the enemy on their right in a similar manner.
While this was happening Hasdrubal was still engaged in leading his forces out of the camp. For up to now he had waited there relying on the strength of the position and convinced that the enemy would never venture to attack him: thus, owing to the unexpectedness of the assault, he was too late in deploying his troops.
The Romans fighting on the wings, since the enemy had not yet occupied the ground on their wings, not only succeeded in safely mounting the ridge, but as the enemy were still forming up and in motion when they attacked, slaughtered some of them by falling on their flank and compelled those who were getting into formation to turn and fly.
Hasdrubal, as had been his original intention, when he saw his troops giving way and in disorder, declined to fight it out to the death,
but taking his money and his elephants and drawing off after him as many of the fugitives as he could, retreated along the River <a class="linkToPlace" target="_blank" href="/place?placename=Tagus&groupId=1000&placeId=1762">Tagus</a> in the direction of the pass over the <a class="linkToPlace" target="_blank" href="/place?placename=Pyrenees&groupId=921&placeId=1650">Pyrenees</a> and of the Gauls who inhabited that part of the country.
Scipio did not think it advisable to follow Hasdrubal, as he was afraid of being attacked by the other generals, but gave the enemy's camp up to his soldiers to plunder.
Walbank Commentary