The melancholy story of the storm runs as follows. On the explosion of the mine at San Roman, punctually at 4.30, all three of the sections of the assault were duly delivered. At the breach the forlorn hope of the King’s German Legion charged at the rough slope with great speed, reached the crest, and were immediately joined by the support, led most gallantly by Major Wurmb of the 5th Line Battalion. The first rush cleared a considerable length of the rampart of its defenders, till it was checked against a stockade, part of the works which the French had built to cut off the breach from the main body of the place. Foiled here, on the flank, some of the Germans turned, and made a dash at the injured rampart of the third line, in their immediate front: three or four actually reached the parapet of this inmost defence of the enemy. But they fell, and the main body, penned in the narrow space between the two enceintes, became exposed to such an overpowering fire of musketry that, after losing nearly one man in three, they finally had to give way, and retired most reluctantly down the breach to the trenches they had left. The casualties out of 300 men engaged were no less than 82 killed and wounded[55], among the former, Wurmb, who had led the assault, and among the latter, Hesse, who commanded the forlorn hope, and was one of the few who scaled the inner wall as well as the outer.

The Guards in their attack, 100 yards to the right of the breach, had an even harder task than the Germans, for their storm was a mere escalade. It was executed with great decision: issuing from the front trench they ran up to the line of broken palisades, passed through gaps in it, and applied their ladders to the face of the rampart of the second enceinte. Many of them succeeded in mounting, and they established themselves successfully on the parapet, and seized a long stretch of it, so long that some of their left-hand men got into touch with the Germans who had entered at the breach. But they could not clear the enemy out of the terre-pleine of the second enceinte, where a solid body of the French kept up a rolling fire upon them, while the garrison of the upper line maintained a still fiercer fusillade from their high-lying point of vantage. The Guards were for about ten minutes within the wall, and made several attempts to get forward without success. At the end of that time a French reserve advanced from their left, and charging in flank the disordered mass within the enceinte drove them out again. The Guards retired as best they could to the advanced trenches, having lost 85 officers and men out of the 300 engaged. The French returned their casualties at 11 killed and 30 wounded.

Wellington’s dispatch, narrating the disaster, gives the most handsome testimonial to the resolution of both the bodies of stormers. ‘It is impossible to represent in adequate terms the conduct of the Guards and the German Legion upon this occasion. And I am quite satisfied that if it had been possible to maintain the posts which they gained with so much gallantry, these troops would have maintained them[56].’ But why were 600 men only sent forward, and no support given them during the precious ten minutes when their first rush had carried them within the walls? Where were the brigades to which the stormers belonged? It is impossible not to subscribe to Burgoyne’s angry comment that ‘the miserable, doubting, unmilitary policy of small storming-parties’ caused the mischief[57]. He adds, ‘large bodies encourage one another, and carry with them confidence of success: if the Castle of Badajoz was stormed with ten or twelve ladders, and not more than 40 or 50 men could mount at once, I am convinced that it was only carried because the whole 3rd Division was there, and the emulation between the officers of the different regiments got their men to mount; although we lost 600 or 700 men, it caused success—which eventually saves men.’

The third section of the assault of October 18, the unimportant attack on the church of San Roman, had a certain measure of success. The mine, though it did not level the whole building, as had been hoped, blew up the terrace in front of, and part of its west end. Thereupon the French evacuated it, after exploding a mine of their own which brought down the bell-tower and much more, and crushed a few of the caçadores and Spaniards[58] who were ahead of their comrades. The besiegers were able to lodge themselves in the ruins, but could make no attempt to approach the actual walls of the second enceinte. So the 6th Division remained behind, within the streets of Burgos, and never came forward or showed themselves.

Such was the unhappy end of this most unlucky siege. All through the day of the assault there had been heavy skirmishing going on at the outposts of the covering army; Souham was at last on the move. On the 19th the Guards’ brigade and the K.G.L. brigade of the 1st Division marched to join the 5th and 7th Divisions at the front, leaving only the line brigade (Stirling’s) to hold the trenches on the north and west sides of the Castle. Two-thirds of the 6th Division had already gone off in the same direction before the storm: now the rest followed, handing over the charge of Burgos city and the chain of picquets on the east side of the Castle to Pack’s Portuguese. There was little doing in the lines this day—the French built up the oft-destroyed parapet of breach III with sandbags, and made an incursion into the church of San Roman, driving out the Portuguese guard for a short time, and injuring the lodgement which had been made in the ruins. But they withdrew when the supports came up.

On the 20th, news being serious at the front—for Souham showed signs of intending to attack in force, and it was ascertained that he had been reinforced by great part of the Army of the North, under Caffarelli in person—Wellington gave orders to withdraw the guns from the batteries, leaving only two of the captured French pieces to fire an occasional shot. All transportable stores and ammunition were ordered to be loaded up. There was some bickering in San Roman this day, but at night the Portuguese were again in possession of the much-battered church.

On the 21st came the final orders for retreat. The artillery were directed to burn all that could not be carried off—platforms, fascines, &c.—to blow up the works on San Miguel, and to retire down the high-road to Valladolid. The three 18-pounders were taken a few miles only. The roads being bad from heavy rain, and the bullocks weak, it was held that there was no profit in dragging about the two guns which had lost trunnions and were practically useless. The surviving intact gun shared the fate of its two ‘lame’ fellows: all three were wrecked[59], their carriages were destroyed, and they were thrown out on the side of the road. The artillery reserve, now reduced to the five ineffective 24-lb. howitzers, then continued its retreat.

On the night of the 21st-22nd, Pack’s brigade and the other troops left to hold the works retired, the covering army being now in full retreat by various roads passing through or around the city. The main column crossed at the town bridge—the artillery with wheels muffled with straw to deaden their rumbling—risking the danger of being shelled in the darkness by the Castle, which had several guns that bore upon it. The long series of mishaps which constituted the history of the siege of Burgos ended by the failure of the plan for the explosions on San Miguel: the French found there next day more than twenty barrels of powder intact. The arsenal in the town was fired when the last troops had passed, but was only partly consumed. Next morning (October 22) the advanced guard of the Army of Portugal entered Burgos, and relieved the garrison after thirty-five days of siege. Dubreton had still nearly 1,200 effective men under arms: he had lost in his admirable and obstinate defence 16 officers and 607 men, of whom 304 were killed or died of their wounds. The corresponding total British casualty list was no less than 24 officers and 485 men killed, 68 officers and 1,487 men wounded and missing [the last item accounting for 2 officers and 42 men]. Almost the whole of the loss came from the ranks of the 1st Division and Pack’s Portuguese, the 6th Division troops having had little to do with the trenches or assaults[60].