The capture of Porto Bello (properly Puerto Bello) was part of a campaign known as 'The War of Jenkins' Ear', which was fought against Spain in the West Indian colonies and was in effect an early stage of the War of the Austrian Succession, 1740-48. When Robert Jenkins, a merchant sea captain, had his ear cut off by a Spanish officer at Havana in 1731 it led to calls in Parliament for war with Spain. During a House of Commons debate in the summer of 1739, Captain Edward Vernon claimed he could take the Spanish town of Porto Bello - a source of Spanish depredation on British shipping on the north side of the Isthmus of Darien between Columbia and Panama - with only six ships of the line. He was promoted to vice-admiral and given the six ships so that he could carry out his promise. These were the 'Burford', Vernon's flagship, and the 'Hampton Court', both of 70 guns; the 'Worcester', 'Strafford' and 'Princess Louisa', all of 60 guns, and the 'Norwich', 50 guns. Vernon's squadron sighted Porto Bello on the night of 20 November 1739. The main obstacle to overcome was the Iron Castle, or 'Castillo de Ferro', at the northern entrance to the harbour, which they attacked at 2.00 p.m. on 21 November and a ferocious battle ensued. When the enemy fire gradually lessened, Vernon signalled for his manned boats to land beneath the walls of the castle. On the morning of 22 November the Spanish governor, Don Francisco Martinez de Retez, sent a flag of truce and accepted the Vice-Admiral's terms of surrender. Public money found in the garrison was distributed by Vernon among his men and the fortifications were then demolished. The surrender terms stated that Vernon received shipping and ten thousand dollars from the treasury as well as brass ordnance. He was also successful in demanding from Panama the release of some South Sea Company men who were imprisoned there.

In this panoramic view from the south-west of the harbour, the Iron Castle lies in the middle distance. It is shown exchanging fire with the 'Burford', in starboard-quarter view, whilend in the left foreground the 'Strafford', and the 'Princess Louisa', can be seen in starboard-bow view. To the right of the 'Burford', and partially obscured by the smoke of her guns are the remaining three ships, in port-quarter view. Beyond is the Spanish shipping at anchor off Porto Bello in the right background, and the nearer port defence, Gloria Castle, is firing her cannon. The land round the harbour is thickly wooded. Scott's representation of the event, with its distorted perspective, draws on the tradition of bird's-eye-view, 17th-century topographical landscape painting.

Scott belonged to the first generation of British marine painters, who worked in the tradition of the van de Veldes and the other Dutch artists who came to practice in London from the 1670s. His reputation chiefly rests on his topographical views of London but he was a very good marine painter, who accepted commissions like this and whose artistic and social skills eclipsed - at least in business terms - those of his slightly earlier contemporary Peter Monamy. He was notably averse to travelling by sea himself but produced many small drawings and watercolours to be incorporated later as details into his oils, such as men rowing and unloading boats, and often drew his ships from models. The painting bears a later inscription in the bottom right hand corner; 'Porto Bello taken by Admiral Vernon in 1740 - for which he received the Thanks of both Houses of Parliament'. The capture had great impact in England, made Vernon a national hero and was the first British victory marked by the production of various popular souvenirs.