The general intended to make a forced march, keeping by the sea-road. A strong advance guard would press forward and occupy the formidable position of Mathia in the rear of the hills. With the main body he intended to seize some heights a few miles behind Torres Vedras, and to cut the road between that place and Montechique, on the direct road to Lisbon, and so interpose between Junot and the capital. At twelve o'clock that night Sir Arthur was roused by a messenger, who reported that Junot, with 20,000 men, was advancing to attack him, and was but an hour's march distant. He disbelieved the account of the force of the enemy, and had no doubt but that the messenger's fears had exaggerated the closeness of his approach. He therefore contented himself with sending orders to the pickets to use redoubled vigilance, and at daylight the whole British force was, as usual, under arms.

Nothing could have suited the British commander better than that Junot should attack him, for the position of Vimiera was strong. The town was situated in a valley, through which the little river Maciera flows. In this were placed the commissariat stores, while the cavalry and Portuguese were on a small plain behind the village. In front of Vimiera was a steep hill with a flat top, commanding the ground to the south and east for a considerable distance. Fane's and Anstruther's infantry, with six guns, were posted here. Fane's left rested on a churchyard, blocking a road which led round the declivity of the hill to the town. Behind this position, and separated by the river and road, was a hill extending in a half-moon to the sea.

Five brigades of infantry, forming the British right, occupied this mountain. On the other side of the ravine formed by the river, just beyond Vimiera, was another strong and narrow range of heights. There was no water to be found on this ridge, and only the 40th Regiment and some pickets were stationed here. It was vastly better to be attacked in such a position than to be compelled to storm the heights of Torres Vedras, held by a strong French army. The advance of the French was fortunate in another respect. On the 20th Sir Harry Burrard arrived in the bay on board a frigate, and Sir Arthur, thus superseded, went on board to report the position of affairs, renewing his recommendation that Sir John Moore should land at Mondego and march to Santarem. Sir Harry Burrard, however, had already determined that his force should land at Maciera, and he refused to permit Sir Arthur's plan of advance to be carried out, and ordered that no offensive step should be undertaken until Sir John Moore had landed.

The advance of Junot, happily, left Wellesley at liberty to act; and disposing his force in order of battle, he awaited the appearance of the enemy. It was not until seven o'clock that a cloud of dust was seen rising above the opposite ridge, and an hour later a body of cavalry crowned the height and sent out a swarm of scouts in every direction. Almost immediately afterwards a body of cavalry and infantry were seen marching along the road from Torres Vedras to Lourinha, threatening to turn the left of the British position. As the British right was not menaced, four of the brigades on the hill on that flank were ordered to cross the valley and to take post with the 40th Regiment for the defence of the ridge.

This movement, being covered by the Vimiera heights, was unseen by the enemy; the 5th brigade and the Portuguese were on a second ridge behind the other, and thus assisted to cover the English left and protect its rear. The ground between the crest on which the French were first seen and our position was so thickly covered with wood, that after the enemy had descended into it no correct view of their movements could be obtained.

Junot had intended to fall upon the English army at daybreak, but the defiles through which the force had to pass had delayed the march, as had the fatigue of the troops, who had been marching all night. From the height from which he obtained a view of the British position it seemed to him that the British centre and right were held in great strength, and that the left was almost unguarded. He therefore determined to attack upon that flank, which, indeed, was in any case the most favourable, as, were he successful there, he would cut the line of the British retreat and pen them up on the sea-shore.

The march of the four brigades through Vimiera to take post on the British left was hidden from him, and he divided his force into two heavy columns, one of which was to attack the British left, and having, mounted the height to sweep all before it into the town; the other was to attack Vimiera Hill, held by Anstruther and Fane.

Brennier commanded the attack against the left, Laborde against the centre, Loison followed at a short distance. Kellermann commanded the reserve of Grenadiers. Unfortunately for the success of Junot's plan, he was unaware of the fact that along the foot of the ridge on the British left ran a deep ravine, that rendered it very difficult to attack except at the extreme end of the position.

"We are going to have our share of the fun to-day," O'Grady said, as he stood with a group of officers, watching the wooded plain and the head of Laborde's column debouching from among the trees, and moving towards the hill.