A full-length portrait wearing flag officer's undress uniform, 1774–1783, although the button-holes are shown grouped in threes as worn by Vice-Admirals, 1783–1787. In the left background is a depiction of the relief of Gibraltar in 1781. The portrait was begun in 1783 and may not have been finished until 1786 and Darby certainly sat to Romney in 1783, 1784 and 1786. He had received his first command in 1747 and his career was uneventful until the Seven Years War, in which he served under Admiral Rodney at the capture of Martinique, 1762. In the American Revolutionary War, 1775–1783, Admiral Keppel's resignation during the crisis following the Battle of Ushant in 1778 left a vacancy for command of the Channel fleet. In 1778 Darby became a Rear-Admiral and a Vice-Admiral the following year, thanks to his association with Sandwich, the First Lord, during the courts martial of Keppel and Palliser in 1779. Thus he unexpectedly came to command the Channel Fleet in 1780 at a time of grave danger for Britain. In April 1781 he relieved Gibraltar from its siege by the Spanish, for the second time during that war, and it is this event which is recorded in the portrait.