When the assaulting party, led by the King's Own, filed out of the trenches, it was saluted with a tempest of shells and grape-shot which blazed in the air, tore up the ground, and menaced the brigade with instant destruction; yet, urged forward by their native ardour and thirst for glory, the soldiers rushed through this dreadful storm of bullets towards the breach, where they encountered difficulties almost insuperable. Many of the King's Own, evincing their inborn valour and contempt of danger, rushed up the breach and perished; others following, shared the same fate. Every exertion and device which the most determined bravery could inspire were repeatedly tried in vain, no man outliving the attempt to gain the ridge. Lieutenant Le Blanc of the Fourth, who led the light infantry company of the regiment immediately after the forlorn hope, particularly distinguished himself, and was the only surviving officer of the advance. At length the British heavy guns were turned against the curtain, and the bullets, which passed a few feet only above the heads of the soldiers at the breach, having produced some effect, another strenuous effort was made to gain the high ridge. The officers and soldiers rushing forward with enthusiastic gallantry, were favoured by the explosion of a mine, and the breach was forced. The town was immediately captured, and the citadel surrendered a few days afterwards.
The gallant behaviour of the King's Own on this occasion is set forth in the following copy of a letter from Major-General Robinson to the colonel of the regiment.
"St. Sebastian, 5th September, 1813.
"My Lord,
"I feel it my duty to inform your lordship of the gallant conduct of the first battalion of the King's Own at the attack of the breach of these works on the 31st August. The first attack was the exclusive duty of the second brigade, consisting of the Fourth, forty-seventh, and fifty-ninth, with a company of Brunswick Oels sharp-shooters; or rather of a thousand men of the brigade; the remainder, to the amount of two hundred and fifty, were in the trenches and waited further orders.
"The Fourth led, and perhaps in the whole history of war there cannot be found a stronger instance of courage and obedience to orders, for the instructions were to make a lodgement on the breach only; there to wait support. The lodgement was effected under the most tremendous fire of grape and musquetry that can be imagined, and our loss was dreadful, that of the Fourth only is twelve officers, nineteen serjeants, and two hundred and thirty rank and file killed and wounded. The other regiments emulated the Fourth, and called forth the acclamations of the generals, and thousands who were looking on. It was not until after three hours hard fighting that the lodgement was certain, after which, by the premature springing of one of the enemy's mines, the town was soon carried.
"This action, so soon after that of Vittoria, requires that I should report the conduct of the regiment in the warmest manner to your lordship, and I feel it but justice to a few individuals, who from accidental causes had opportunities of doing more than others, to mention their names. Captain Williamson commanded the regiment, and was twice wounded after he had reached the top of the breach. Captain Jones succeeded, not only to the command of the regiment, but on my being obliged to quit the field, to that of the brigade, and acquitted himself most admirably. My acting aide-de-camp, Captain Wood, left me at my request, and by his judgment and example contributed materially to the success of the daring attempt. The three are excellent officers, and will ere long, I hope, prove themselves equal to the duties of a higher station.
"I have, &c.
"F. P. Robinson,
"Major-general, commanding second brigade,
fifth division.
"To General the Earl of Chatham, &c."
This brilliant display of British valour and heroism by the second brigade, was attended with the loss of two majors, eight captains, twenty-six lieutenants, twelve ensigns, forty-seven serjeants, six drummers, and five hundred and eighty-nine rank and file killed and wounded; among whom were the following officers of the King's Own:—Lieutenants Francis Maguire, Jonas Fawson, W. S. A. Carrol, J. P. Jameson, and Ensign Charles Montford killed; with Brevet Lieut.-Colonel John Piper, Captains John Williamson, John Wynne Fletcher, Lieutenants Francis Le Blanc, George Heywood, William Clarke, and Frederick Hyde, wounded.