Beresford caught up with Baird in Capetown. Baird then sent him after Janssens, who had withdrawn into the interior in the Hottentots Holland Kloof area with his defeated force. He caught up and made contact with the Dutchman, having assumed a position in Stellenbosch on 14 January, and secured the environs. When Baird arrived the following day, Janssens surrendered after further discussions. In his dispatch home, Baird praised Beresford’s ‘spirit of conciliation and perseverance’.12
Up to this point the British expedition had followed its instructions and achieved its objectives with little loss. Baird’s and Popham’s orders provided (in the absence of a negotiated surrender) for the capture of the Cape with the granting to the inhabitants the continued enjoyment of their private property, usages and religion as nearly as might be possible consistent with the terms granted in the previous war when it had been occupied by Britain. Baird was then to send on to India the troops designated for that service. In the event of it being decided that an attempt to capture the Cape was not viable (there was concern the French might have fortified it by means of troops and provisions on vessels that had escaped from Rochfort), the instructions were for that part of the force not designated for India to return to St Helena to await further instructions, and in the event these were not forthcoming within fifteen days, to return to Cork, calling at Faial in the Azores in case instructions had reached that island.13 There was no element of discretion that would allow for the expedition that Baird and Popham subsequently determined upon.
The renewal of the conflict with Spain offered the opportunity to weaken Spain as a military power and to open up trading opportunities, particularly in South America. The latter objective was particularly important in mercantile circles threatened by the loss of British and Irish trade with continental Europe.
One of the most vociferous advocates of British intervention in South America was Sir Home Popham. He had been trying to interest the British government in South America for some years. However, the attack on the Rio de la Plata in 1806 which now took place was pure opportunism and had not been sanctioned in advance by the British cabinet.14 While in Capetown, Popham apparently heard from a number of sources that the Peruvian treasure (in fact primarily silver from the mines around Potosi in modern-day Bolivia, then part of the Viceroyalty of Peru) was on its way to Buenos Aires for transhipment to Spain.15 With communications to London taking perhaps three months in each direction, there was no time to seek instructions. Popham approached Baird, and after some initial resistance persuaded the military commander to authorise Popham to take part of his fleet and some 1,400 troops from Capetown to support the enterprise. The voyage provided for a stopover at St Helena, where it was hoped that the expedition might pick up additional troops and artillery.16
Baird determined to appoint Beresford to command the expeditionary force, stating to Lord Castlereagh that he had: ‘confided the command to an officer of rank and recognized ability, wise and zealous.’ He further authorised the appointment of Beresford as Lieutenant-Governor if he should get possession of ‘the Spanish establishment on the River Plate’.17
The core of Beresford’s force (some 864 men) was made up of the 1st Battalion of the 71st Regiment of Foot, commanded by another Irishman, Lieutenant Colonel Denis Pack. Beresford and Pack were firm friends, though it is not known whether this factor played any part in the selection of the 71st Regiment to accompany Beresford.18 Popham had wanted to take a different regiment, whose commanding officer was a close friend of his own.19 Additional firepower was to be supplied by Royal Marines, Royal Artillery members and a picket of the 20th Light Dragoons, as well as sailors from the fleet accompanying Beresford’s force.
Following the capture of Capetown, the 71st had been quartered at Wynnberg, about 7 miles outside the town. Once again secrecy was the order of the day and the speculation in Capetown concerned Macao or Manila as the destination of the expedition, given that the Ile de France was considered too strong a target. Popham’s predeliction for South America was such that it was not long before opinion fixed on a marauding expedition along the coast of Peru. When later they heard of Beresford’s success in capturing Buenos Aires, the reaction was one of incredulity that a city of this size could be taken by one regiment.20 On 12 April 1806, the 71st Regiment and the other members of the expedition embarked, and Popham’s fleet, which sailed on 20 April, arrived in Saint Helena nine days later. On the way there contact had been lost with The Ocean, one of the transports carrying some 200 men, but fortuitously this was waiting for the fleet when it arrived at the entrance to the Rio de la Plata. In Saint Helena, Beresford acquired some 250 additional soldiers including artillerymen and two 5½-inch howitzers. In all this little army numbered little more than 1,600 men.21
Arriving in the Rio de la Plata in early June, Popham and Beresford disagreed on their first objective. Beresford sought to strike against Montevideo rather than Buenos Aires, on the basis that Montevideo was reportedly well fortified and that it would be preferable to strike the stronger position first while the British force had the element of surprise and the men were fresh. He was overruled by Popham, allegedly on the basis that provisions, which were apparently in short supply, would be easier to obtain in Buenos Aires.22 However, it seems not unreasonable to suppose that the suspected presence of ‘Peruvian’ silver in Buenos Aires in transit to Spain may have contributed to Popham’s preference for an attack on Buenos Aires rather than Montevideo.23 The troops then transferred from the men-of-war to frigates and transports as the former were too big to proceed up-river. The scene was set for a landing, though Beresford’s disclosure that Baird had commissioned him as Major General on the eve of his departure from the Cape (12 April) upset Popham, who later lodged a complaint with the government in this respect.24
On 24 June, the force was off Buenos Aires and the Spanish Viceroy, Rafael Marquis de Sobremonte, was advised of its arrival while attending the theatre that evening. He had been warned in general terms of the presence of the British squadron in the Rio de la Plata some weeks earlier, in response to which Sobremonte had taken certain defensive measures. Buenos Aires at that time was a town of between 40,000 and 50,000 inhabitants.25 There was a fort near the river with thirty-five 24lb guns and assorted other ordnance. However, the city was short of regular troops, for some of those designated to go there were still in northern Spain. A number of local regiments were augmented by a militia. When he was first warned of the British presence, Sobremonte called out the militia and stationed troops in Quilmes, Olivos and along the line of the Rio Riachuelo; the former to cover anticipated landing points, and the latter to create a defensive screen outside the city. However, the Viceroy’s reaction to the landing of the British was to abandon Buenos Aires and to proceed inland towards Córdoba with some 600 troops and sixteen wagons loaded with the state treasure and the valuables of wealthy citizens. He left his aide-de-camp (ADC), Hilarión de la Quintana, to resist the British, and if necessary to negotiate terms.26
The following day (25 June) Beresford disembarked his forces, amounting to probably less than 1,450 men, at Quilmes, approximately 12 miles from Buenos Aires.27 Having seized the beachhead, the small force spent the night near Reducción de Quilmes before proceeding towards Buenos Aires. The next day the British encountered a Spanish force estimated variously to be 2,000–3,000 strong with cavalry and cannon drawn up in a line. Beresford sent the 71st Regiment under Pack forward with bagpipes playing, while keeping the Saint Helena infantry in reserve. The British troops brushed aside resistance following a short but sharp fight. The Spanish retreated to a small village called Barracas, burning the bridge over the river Riachuello, but early on the morning of 27 June, following a brisk exchange of fire, Beresford’s troops crossed the Riachuello on a pontoon bridge made up of small boats and planks, and quickly gained possession of Barracas.
Beresford sent one of his ADCs, Alexander Gordon, to summons the city of Buenos Aires. Quintana sought terms for surrender, but Beresford refused conditions save such as he was pleased to offer. On the afternoon of 27 June the British entered Buenos Aires and took possession of the fortress. From disembarkation to the surrender of the fortress the British force lost only one man killed and a further twelve