Although third-in-command at Trafalgar, Northesk played very little part in the battle, or in the planning that preceded it. He and Nelson had not served together before – although Nelson, as was his custom, made a point of getting to know his new subordinate, and of winning his confidence. He dined with him privately on at least two occasions in the weeks before the battle and consulted him on the appointment of officers to the Britannia.

Northesk was born in Hampshire on 10 April 1756. His father, the sixth earl, had also served in the Royal Navy and so the young William went to sea in 1771, the same year as Nelson. He served as a lieutenant in Admiral Sir George Rodney’s flagship, hms Sandwich, at the victory over the French on 17 April 1780, and was promoted commander for his part in the battle. He reached post rank in April 1782 and commanded the frigate hms Enterprise. Ten years later, he succeeded to the earldom.

During the war against Revolutionary France, he commanded frigates until his appointment to the Monmouth (64), an East Indiaman converted on the stocks, in 1796. He was still in command when his ship’s company was involved in the Mutiny at the Nore, in 1797. Having been imprisoned on board for a while, he was then asked by the delegates to take their demands to the King, which he agreed to do. When the demands were rejected, he remained in London and resigned his command.

In 1803, he was appointed to command the First Rate battleship Britannia in the Channel Fleet and when he was promoted rear admiral in April 1804, he remained in her. He was part of a detachment sent south under Sir Robert Calder in August 1805 to assist in blockading the Combined Fleet in Cadiz.

At Trafalgar, the Britannia was in Nelson’s line and was hotly engaged with a number of enemy ships, including the Santissima Trinidad, suffering fifty-two casualties. Northesk was made a Knight of the Bath and was given the naval gold medal, the freedom of the City of London and a vase worth £300 from the Lloyd’s Patriotic Fund.

He did not serve at sea again, although he was created rear admiral of the United Kingdom in 1821 and served as commander-in-chief at Plymouth during 1827–30. He died in Albermarle Street, London, on 28 May 1831 and was buried in St Paul’s Cathedral alongside Nelson and Collingwood.

CSW