After the battle of the Coa the French advanced on 27 July to Pinhel, and Picton fell back to Carapichina. After the fall of Almeida, which, like Ciudad Rodrigo and in accordance with Wellington's policy, it was not attempted to succour, Masséna prepared to enter Portugal. Wellington made his dispositions accordingly, and Picton and the third division were posted at Laurosa; but, in the middle of September, Masséna changed his plans, suddenly concentrated his whole army, and marched rapidly along the right bank of the Mondego to secure Coimbra before he could be opposed by the allies. Wellington retired by the left bank, and, throwing his army across the river, took up a position, on 20 Sept. 1810, in rear of the Busaco ridge. Picton was posted to defend the ridge from San Antonio de Cantara to the hill of Busaco, about a mile and a half in extent, with General Leith's corps on his right and Sir Brent Spencer's division on his left. On 25 Sept. Picton, in obedience to orders, had detached Major-general Lightburne's brigade to reinforce the first division (Spencer's), and his force was in consequence reduced to three British and two Portuguese regiments. On the evening of the 26th Picton detached the strongest regiment of the division (the 88th) nearly a mile to the left to keep touch with the first division and observe that part of the line which was not occupied by any troops. The French attack commenced before daylight on the 27th, and was mainly directed on the pass of San Antonio, where Picton was. Fourteen guns opened on the pass, and a large column attempted to force it; but so incessant and destructive a fire was maintained by the third division that the French were ultimately compelled to abandon the attempt. In the meantime a heavy column of the enemy penetrated on the left of Picton's position, close to the hill of Busacos, where were the 88th regiment and four companies of the 45th regiment. With the assistance of a Portuguese regiment, which opportunely arrived, he succeeded in driving the enemy across the ravine in great disorder. The enemy having been foiled at all points, the battle was won by the allies, who on 29 Sept. took up a position to cover Coimbra. On 1 Oct. the French attacked this position, driving in the British outpost. A retreat was ordered, and by 7 Oct. the allied army had retired behind the lines of Torres Vedras, where they went into winter quarters.
Picton and the third division had to defend the lines extending from Spencer's division on the right, by the village of Pantaneira, across a kind of ravine, to the fourth division (Cole's) on the left. The allies were now occupying an impregnable position behind two lines of defence, whence they could watch the enemy's movements and defy his attacks. They were in a friendly country, with Lisbon in their rear and a British fleet lying in the Tagus, where ample supplies of corn and ammunition were constantly arriving from England. On the other hand, Masséna, with an army twice as strong as that of the allies, had fallen into the trap, and had only discovered it on his arrival at Torres Vedras. Picton wrote in November that Masséna was probably waiting for reinforcements. The French made several demonstrations during the winter, but no serious attempt on the lines of the allies, and on 4 March 1811 their retreat commenced. On the 6th the allies were after them, and Picton's division bore the chief part in the pursuit. On the 11th this division came up with the enemy's rearguard near Pombal, and for the following seventeen days almost incessantly harassed the enemy's left. Finally, on 29 March, the French were dislodged from a position which they had taken on the height of Guarda, the strongest and most defensible ground Picton had ever seen. The most important part of the day's action fell to Picton, whose exertions throughout this pursuit were indefatigable. Awake before daylight, he prepared his division to move as soon as there was light enough to see the track. Constantly at its head, encouraging and directing it, he was within sight of every man in his division.
Masséna having laid waste the country in his retreat, the pursuit had to be relaxed on account of the difficulty of obtaining provisions. By 5 April 1811 the whole of Portugal, with the exception of Almeida, had been freed from French troops at the point of the bayonet, and the allied army invested Almeida. On 2 May Masséna advanced on Almeida. The battle of Fuentes d'Onoro followed on the 5th, when the principal share in the fighting once more fell to Picton's division. The French were defeated, and the allies entered Almeida.
Masséna was recalled, and Marmont succeeded to the command of the French. Wellington went to Badajos, which was besieged by Beresford, directing Picton's and the seventh divisions to follow. On 24 May Picton arrived at Campo Major, and on the 27th, crossing the Guadiana, he took up his position on its left bank for the investment of Badajos, the seventh division being established on the right bank, and Beresford employed in watching Soult. After five weeks of unceasing effort, with inadequate means, and
