When it became clear that Napoleon was planning an invasion of Britain, Moore was put in charge of the defence of the coast from Dover to Dungeness. It was on his initiative that the Martello Towers were constructed (complementing the already constructed Shorncliffe Redoubt), following a pattern he had been impressed with in Corsica, where the Torra di Mortella, at Mortella Point, had offered a stout resistance to British land and sea forces. He also initiated the cutting of the Royal Military Canal in Kent and Sussex, and recruited about 340,000 volunteers to a militia that would have defended the lines of the South Downs if an invading force had broken through the regular army defences. In 1804 Moore was made a Knight Companion of the Bath and promoted to Lieutenant-General. In 1806 he returned to active duty in the Mediterranean and then in 1808 in the with Edward Paget to assist the Swedish. Disagreements with Gustavus IV soon led to his being sent home where he was ordered to Portugal in July 1808.