seven o'clock
On the 20th Sir Harry Burrard arrived in the bay on board a frigate , and Sir Arthur , thus superseded , went on board to report the position of affairs , renewing his recommendation that Sir John Moore should land at Mondego and march to Santarem .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 .