In the center the fight was hot.

The king's foot had come up the hill and poured volley after volley into the parliament ranks.

Hand to hand the infantry were fighting, and gradually the Roundheads were giving way.

But now, as at Marston, Cromwell, keeping his Ironsides well in hand, returned from the defeat of Langdale's horse, and fell upon the rear of the Royalists.
Fairfax rallied his men as he saw the horse coming up to his assistance.
Rupert's troopers were far from the field, and a panic seizing the king's reserve of horse, who had they charged might have won the day, the Earl of Carnewarth, taking hold of King Charles' horse, forced him from the field, and the battle ended, with the complete defeat of the royal troops, before Rupert returned to the field of battle.
The Royalists lost in killed and prisoners five thousand men, their twelve guns, and all their baggage train, and what was of even greater importance, the king's private cabinet, which contained documents which did more to precipitate his ruin even than the defeat of his army.

Here were found letters proving that while he had professed his desire to treat, he had no intention of giving way in the slightest degree.