Ceded to Great Britain in 1714 by Spain following the War of the Spanish Succession, its capture by France threatened the British naval position in the Western Mediterranean and it was returned after the Treaty of Paris (1763).

Although considered vital for control of the Western Mediterranean, it was also extremely vulnerable, since the Spanish deeply resented British occupation, while it was only two days sail from Cádiz, and one from the French naval base at Toulon.

[6] A Parliamentary committee later set up to investigate the island's loss noted the poor state of its defences, with crumbling walls and rotten gun platforms, while over 35 senior officers were absent from their posts, including the governor of Fort St Philip, and the colonels of all four regiments in its garrison.

Informed of Richelieu's preparations in mid March, Blakeney had substantially strengthened his fortifications but the presence of numerous non-combatants, including over 800 women and children, meant the garrison would quickly run short of supplies.

[13] His professional colleagues were far more critical; William Cunninghame, his chief engineer and deputy, strongly objected to the surrender, which he considered premature, and listed numerous deficiencies in the conduct of the defence.