Despite Sir Robert Walpole's best efforts to avoid a conflict, the long-expected war between England and Spain - known to history as the War of Jenkins' Ear - was declared on 23 October 1739. In advance of the formal declaration, a squadron of nine ships commanded by Vice-Admiral Edward Vernon wsa detached from the fleet at Spithead and sent to the West Indies. Vernon, who was also a Member of Parliament, had long maintained that if he were given six ships he could take Porto Bello, the principal Spanish fortress in Central America. He had, in fact, so irritated the Government with his persistent bragging that they decided to test his theory and dispatched him to Jamaica where he arrived on the day war was declared. After two weeks' preparation, Vernon and his six ships left Port Royal on 5 November and anchored off Portol Bello on the 20th. The town was situated on the north coasts of the Isthmus of Darien, near modern Colon, and was strongly defended by a castle and two outer forts. The next day, 21 November, Vernon began his assault by bombarding the 'Iron' Fort and then landed his marines who soon subdued it. The other two garrisons, especially the larger force in Gloria Castle, proved more troublesome and their guns pounded Vernon's ships for most of the day. What Vernon did not realise, however, was the poor calibre of all the defending forces who clearly regarded their situation as hopelesss. Early the following morning, and much to Vernon's surprise, the Spaniards hoisted a white flag and surrendered without further bloodshed.
It was a brilliant tactical victory, as much due to Vernon's audacity as to the weakness of his opponents, and in England he was feted as the hero of the hour. It was doubly unfortunate therefore that neither the remainder of the war nor Vernon's subsequent career were able to match this early triumph.