Not only did the British government lend its encouragement, through Lord Cochrane, to the filibustering expedition from the United States with which Miranda hoped to revolutionize Venezuela, but about the same time it sent an expedition against the provinces of the Plate. This attack, like the assistance given to Miranda, was ill-timed and not properly followed up. The policy seems to have been outlined by Pitt, but was put into execution after his death by the short-lived ministry of Grenville and Fox. The government of the Duke of Portland, which succeeded after a few months, and in which Castlereagh and Canning were the most conspicuous figures, did not deem it expedient to follow up the undertaking.[25] In fact, the fate of the expedition was already sealed when Portland came into power. The victory of Trafalgar had given the English control of the Atlantic. A force of some 6,000 men was dispatched to the South Atlantic without its destination being known. It proceeded to Rio Janeiro, Portugal then being in alliance with England. The viceroy of the Plate became alarmed and prepared to defend Montevideo, which he thought would be the first point of attack. The expedition, however, passed by and proceeded to the Cape of Good Hope, which it wrested from the Dutch. In 1806 a dash was made from the Cape for the river Plate. Sir Home Popham commanded the fleet, and General Beresford the land force, which amounted to 1,635 men. On June 6 the squadron arrived at the mouth of the Plate. The ships had some difficulty in ascending the river, but on the 25th they came to anchor at a point fifteen miles below Buenos Aires. The city was captured with little or no resistance, the inhabitants having been led to believe that the British had come to liberate them. The contents of the public treasury were handed over to the invaders. The inhabitants were required to swear allegiance to George III, private property was respected, the free exercise of their religion was allowed, and all officials who took the oath were continued in office. When Beresford refused to proclaim the independence of the province, or to give any assurance for their future independence, the inhabitants, who had now learned how insignificant the invading force really was, began to prepare for resistance. A leader was readily found in the person of Jacques Liniers, a Frenchman, who had been for thirty years in the service of Spain. He and Juan Martin de Puyrredon began an organized movement for the expulsion of the English. On the 12th of August, Beresford, who had remained all this time without reinforcements, was compelled to surrender. Troops ordered to his support from the Cape did not arrive until later. Sobremonte, the viceroy, had deserted Buenos Aires and established himself at Montevideo. The people of Buenos Aires, therefore, deposed him and chose Liniers in his place.