When Anson returned to England in the autumn of 1739 Anglo-Spanish relations were in crisis, with the opposition demanding war, which would necessarily be based on amphibious expeditions against Spanish colonies in the Caribbean and the Pacific coasts of Mexico and South America.

At first, English plans to attack Spanish interests were on a grand scale. While the main force would go to the Caribbean, a powerful expedition would travel via the Cape of Good Hope to seize and hold the Philippines, while another expedition would round Cape Horn to raid Spanish America's Pacific coast and encourage the colonists there to rebel against Spain. Once the ex-colonies were independent, it was assumed that the grateful settlers would negotiate favourable commercial treaties with their liberators. 

However, as the months passed this ambitious scheme to dismember Spain's colonial empire and establish British predominance in the Pacific shrank dramatically. The expedition to the Philippines was dropped, and Anson was chosen to command a smaller squadron against the remote, ill-defended Pacific coastline. 

He was directed to raid and plunder the Spanish settlements on the western coast of America, attack Panama if the Caribbean expedition managed to establish a foothold on the opposite side of the isthmus and capture the annual Manila galleon. Along the way, he was to foment rebellion by the native population against the Spaniards, or by Spanish colonists against imperial authority, which, in turn, might lead to British commercial access to rich new markets.

To accomplish those objectives, Anson was given, apart from his own Centurion, the 50-gun fourth rates Gloucester and Severn, the 40-gun fourth rate Pearl, the 28-gun sixth rate Wager (, the 8-gun sloop Tryal and two storeships. While he had been promised a regiment of five hundred regular infantry, Anson ended up embarking a pathetic rabble of newly recruited marines, invalids and garrison troops, some of them pensioners from Chelsea Hospital.

Preparations for the expedition were slow and frustrating. An inept administration and contrary winds meant the squadron did not finally sail until 18 September 1740. 

© Ian Hughes 2017