La Clue was attempting to evade Boscawen and bring the French Mediterranean Fleet into the Atlantic, avoiding battle if possible; he was then under orders to sail for the West Indies. Boscawen was under orders to prevent a French breakout into the Atlantic, and to pursue and fight the French if they did. During the evening of 17 August the French fleet successfully passed through the Strait of Gibraltar, but was sighted by a British ship shortly after it entered the Atlantic. The British fleet was in nearby Gibraltar, undergoing a major refit. It left port amidst great confusion, most ships not having their refurbishments completed, with many delayed and sailing in a second squadron. Aware that he was pursued, La Clue altered his plan and changed course; half his ships failed to follow him in the dark, but the British did.