Many of the smaller actions that were undertaken against the British by the Cubans were by volunteer forces recruited by veteran fighters, who had not been associated with the army proper, and their manner of waging war was of the kind called guerrilla warfare. Nevertheless they did active and efficient work and had they not been hindered and restrained by orders from the regulars, they might have accomplished much more. The Lieutenant Diego Ruiz lost his life in such an enterprise. Another famous guerrilla, the valiant fighter known as Pepe Antonio, had won the esteem of the whole army by his courage. He had collected a force of three hundred men and was planning an ambitious assault upon the enemy, when he was called to report to Colonel Caro, who commanded the encampment at Jesus del Monte and San Juan. Colonel Caro, who had not during the siege distinguished himself by any extraordinary achievements, not only censured Pepe Antonio severely, but discharged him. The valiant patriot hero of many daring exploits was so grieved by this injustice that he died within five days.

Among these side plays of the great siege an expedition led by Colonel Gutierrez had some successful encounters with the British. D. Luis de Aguiar and D. Laureane Chacon, too, who had gathered under their command the brave youths of the country side, were untiring in their efforts to weaken the British. They prevented them from establishing a cordon and cutting communication with the fort and were themselves enabled uninterruptedly to secure provisions and supplies with which to carry on their operations. Less fortunate was the attack upon Cabanas by D. Juan Benito Lujan with a thousand militia men from the interior of the island. At daybreak, on the twenty-second of July, according to the British officer, the Spanish at el Morro, having been enforced by twelve hundred men from the town, furiously attacked the British. But Brigadier Carleton directed so fierce a fire against them that their forces were driven into the water. He describes them as having consisted mainly of militia, some seamen, mulattoes and negroes. They lost four hundred dead, many wounded and seventy prisoners. A violent cannonade followed, during which Carleton was wounded.

While the British troops were encamped from La Cabanas to Cojimar they made many looting raids in the neighborhood, extending their incursions as far as San Miguel and Santa Maria del Rosario. They not only ransacked the churches for their treasures, but also private estates, and took away whatever they could carry. They had approached el Morro by the bulwark of Pina and a body of forty to fifty men in the shelter of some rocks maintained an incessant gunfire. The garrison of the fort, which was being steadily reduced by the rain of bombs and grenades, wanted to make a sortie into the open country, hoping there to be reenforced. Remaining in el Morro was becoming more and more perilous, because the enemy had undermined the fortress. D. Luis de Velasco, broken down by the strain and overwork received a blow on the shoulder, which temporarily disabled him. His aide, Mentes, was likewise wounded, and the two were replaced by D. Francisco Medina and D. Manuel de Cordova. During their absence nothing was done, for the peasantry, fond as they were of Velasco, were reluctant to fight and perhaps die under the command of another. Mentes returned on the third day, appointed Lieutenant-Colonel, and, joined by D. Juan Benito Lujan, who commanded one thousand men of Tierradentro and some colored troops from the fort, attempted a sally. But the British on the heights threw themselves upon the Cubans and overpowered them. The loss on both sides was so great, however, that the enemy had to ask for a truce to bury their dead. As the British said, the Spanish were valiant, but they had no head. If there had been at their head a man of foresight, and if unity of command had been insured at the beginning, the disaster might have been avoided.

The British forces were at this time beginning to suffer painfully for want of water and lack of fresh provisions. Five thousand men, and a great proportion of officers among them, were unfit for duty. But the arrival of North American troops under convoy of the Intrepid of sixty-four guns, revived the spirit of the expedition. The North Americans had lost a ship of forty guns and six transports in the old straits of Bahama, but the people were saved and encamped upon the shores, and the British Admiral sent frigates for them. One thousand and four hundred men under Brigadier Burton reenforced Col. Howe on the west side. The Cuban defense was also encouraged in these days, for Velasco, who had been wounded on the sixteenth of July, with second, Mentes, forced to seek medical care in the city, returned to his post at el Morro on the twenty-fourth. During the siege the Spanish vessels, with the exception of the frigate Perla, which was sunk by the foe, were singularly inactive. The critical and decisive moment of the siege came on the thirteenth of July, when at two o'clock in the afternoon the British sprung their mines. Through the breach they rapidly entered and captured the battery of San Nicolas. Although the garrison was so terrified that not a few soldiers had fled, the remaining offered a brave opposition to the invaders. D. Fernando Parrayo and thirteen men, supported by two cannon, fought heroically, while the British forces poured into the port. The British officer gives due credit to the Cuban commanders who desperately tried to save the honor of their country. He writes:

"The Marquis de Gonzales, commander of a man of war, etc., second in command of the fort, fell bravely endeavoring to animate and rally his people. Don Luis de Velasco, also Captain of the Reina man-of-war, soon after shared the same fate endeavoring to defend the colours of the fort, round which he had made a breastwork and had collected about 100 men, who soon fled and left him to that stroke he seemed to invite and wait for; for being shot through the breast he fell, offering his sword to the conquerors. Confusion and fright ensued, and as much slaughter; for near 400 of the enemy fell by the sword; as many more taken prisoners to whom the soldiers had generously given quarters, though no ways obliged by the rules of war. English colours were soon flying on the fort, that were welcomed by the loud huzzas of all the rejoiced army and navy. A parley ensued, and D. Luis de Velasco (not yet dead) was at his own request sent to breathe out his last at the Havana, where he expired a day after, leaving a name behind and a character that justly merited admiration and esteem from his opposites as respect and love from his confederates."

The historian Blanchet also reports that the British showed due reverence to the dead leader and that hostilities were for that reason suspended during the following day. They received a reenforcement of troops from New York on the second of August; but they had fallen in with three French men-of-war and some frigates on their passage, who took five or six transports with about five hundred men. Their forces were being decimated by the climate and the hardships. The British witness writes that finishing the batteries on Cabanas cost the lives of many poor seamen who were obliged to be day and night filling vessels with water for the men at work. Some men-of-war were sent down with transports to Mariel, for want of men made it unsafe for them to remain any longer on this most open and frightful coast, where the Spaniards as well as West Indians expressed their surprise and dread at seeing such a fleet ride so long in such a season.

When the British entered el Morro, they found only one hundred and two bronze cannon of various calibres, two hundred iron cannon, nine bronze mortars, two iron mortars, four thousand one hundred and fifty-seven rifles, five hundred hand grenades, four hundred and seventy empty grenades of various quality, seventeen thousand four hundred and four cannon balls, thirty quintals of rifle balls, one hundred and twenty-five thousand cartridges and five hundred quintals of powder. The sorrow at being forced to give up el Morro was great. Supported by the vessel Aquilon the quick fire from la Punta and the bulwarks of the place promptly demolished the fort. The Cuban vessels retired to the interior of the bay, fearing the bombs from la Cabanas. The commanders for the same reason sought shelter in the hospiteum of St. Isidore, which was situated at the point farthest away from the fire. Yet the determination to continue to resist the invaders prevailed and a battery was formed on the elevation of Soto, where the fort of Attares was located, and fortifications were continued to be strengthened wherever it was possible.

The batteries of the British were completed on August tenth, and Lord Albemarle summoned the city to surrender. But Governor Prado relied upon reenforcements promised him by the governor of Santiago de Cuba and hoped also for the possible arrival of a French squadron, so he refused. The people, too, were opposed to surrender, for they had within the last six days received reenforcements from several sides; two hundred and twelve rifles and ammunition from the town of Cuba, five hundred more from Jagua and fifteen hundred on the very last day. However, the fierce fire which the British opened against Havana at daybreak on the eleventh of August, induced the commander of the Cuban forces to give up the last hope. About noon the Spanish ceased firing and at three o'clock in the afternoon flags of truce appeared everywhere. The governor sent word that Havana was ready to capitulate.

According to the British officer's journal the victors took possession of the town and port of Havana on the next day; they also became the owners of nine ships of the line, of seventy four and sixty four guns, two very large ones on the stocks, nearly completed, about twenty-five loaded merchant ships; nearly three million dollars belonging to the King and the Royal Company; about six hundred pieces of cannon, and great magazines of stores and merchandise of all kinds. He continues:

"But the most grateful at the time was, that it furnished us with fresh provisions, rest and shelter for the many thousands poor sick wretches we had in our camp and hospital ships, all mouldering away for want of nourishment when their disorders had left them. Our battalion is so weak that we have not above one hundred and fifty men fit for duty. I am told the navy is badly off. Our loss of killed and wounded is very trifling in comparison to that of the enemy. Theirs amounts to upwards of six thousand killed and dead of their wounds since, and of sickness."