A half-length portrait to left in a painted oval wearing captain's, over three years, full-dress uniform, 1774–87. The background consists of blue sky and loosely painted clouds. The painting is a version of BHC2976, which shows Locker dressed in civilian clothes, which may have been earlier, although he appears younger in the face in the present example.

While in command of the 'Lowestoffe', 32 guns, in 1777, he became a firm friend of his lieutenant, Horatio Nelson, a friendship which continued until Locker's death. Locker was interested in art and befriended artists such as the marine painter Dominic Serres, who also painted his portrait. Indeed, as Lieutenant-Governor of Greenwich Hospital from 1793, he conceived the idea of a naval picture gallery in the Painted Hall. The plan was eventually put into effect by his son, Edward Hawke Locker, in 1823–24. This painting was engraved by W. Ridley in 1801, just after Locker's death. It was presented to the Naval Gallery of the Hospital in October 1830 by Edward Locker, in substitution for another portrait of William by Abbott, which Edward had previously given to the Gallery on its foundation in 1824 at the request of the Hospital Directors. The Abbott is presumably the later portrait (c. 1795) which is now BHC2845, though its provenance between 1830 and 1961, when acquired, is uncertain. At the same time as the 1830 exchange, Locker also gave the Naval Gallery a painting of the 'Experiment' taking the 'Telemaque' in 1757 by Dominic Serres (now BHC0381). Stuart was an American painter who was also active in England and Ireland. He was in London from 1775 until 1787, where early in 1775, he entered the studio of Benjamin West (1738–1820) for whom he painted drapery and finished portraits. Stuart exhibited for the first time at the Royal Academy in the spring of 1787. He maintained an expensive London establishment, and had considerable success as a fashionable portrait painter to both English and American sitters who found themselves in London. However, in 1787, Stuart fled to Dublin – almost certainly to escape his creditors – where he remained for five years. In the spring of 1793, he returned to America, leaving behind scores of unfinished canvases. He subsequently lived and worked in New York, and then Philadelphia, where George Washington posed for him during 1795. He moved to Boston in 1805 where he remained for the rest of his life, both painting and advising fellow artists. See also BHC2976.