McClure, Sir Robert John Le Mesurier (1807–73), Royal Navy officer and Arctic explorer, was born 28 January 1807, at the Rectory, Main St., Wexford, son of Capt. Robert McClure of the 89th Foot and his wife Jane, daughter of Archdeacon Elgee, rector of Wexford. His father died before his birth and he initially lived at the home of his maternal grandfather. When he was four years old, his godfather, Gen. John Le Mesurier, hereditary governor of Alderney, took him into his home there. In 1819 he went to Eton, later attending the Royal Military College at Sandhurst. He did not want a military career, however, and ran away to France before entering the Royal Navy as a midshipman in 1824. In 1830 he passed his examination for lieutenant and took part in HMS Terror’s Arctic expedition (1836–7) under Capt. Sir George Back. After his return he was promoted to full lieutenant (September 1837) and subsequently served aboard Hastings and Niagara on the Canadian station (1838–9). During his time there he captured a notorious outlaw named Kelly who was carrying out raids along the Canadian border. The government had offered a reward of £5,000 for Kelly but, because McClure captured Kelly in American territory, it refused to pay. He then served aboard HMS Pilot in the West Indies (1839–42), and in 1842 was appointed to command the receiving ship, HMS Romney, in Havana.
After a period with the coastguard (1846–8), he volunteered to serve as first lieutenant on HMS Enterprise and sailed to the Arctic with Sir James Clark Ross. This expedition was undertaken to find the missing explorers Sir John Franklin and Capt. Francis R. M. Crozier (qv) and their men. Promoted commander (November 1849), McClure was appointed second-in-command to Capt. Richard Collinson's Arctic expedition as captain of HMS Investigator. On 20 January 1850 Investigator sailed from Plymouth in company with Enterprise, but the two ships were separated in a gale (April). He rounded the north-west point of America and discovered a channel that he christened the ‘Prince of Wales Strait’. By 12 September 1850 the ship was locked in the ice and exploring parties were sent out on foot. On 26 October 1850 McClure ascertained that the strait opened into Melville Sound, and realised that he had discovered a north-west passage. However a document, written by Sir John Franklin, was discovered by Capt. (later Admiral Sir) Leopold McClintock (qv) at Cape Herschel in 1859, which would seem to prove that Franklin's party had discovered a north-west passage in 1845. In September 1851 Investigator was again trapped by ice in the Bay of Mercy and McClure's party spent another two winters trapped in the Arctic. On 6 April 1853 they were relieved by a sledge party from HMS Resolute under the command of Lt. Pim, part of an expedition commanded by Capt. Henry Kellett, RN. McClure and his crew were fêted as heroes on their return to England in September 1854. He was knighted and promoted captain, the promotion back-dated to 18 December 1850; also, the crew of Investigator were voted an award of £10,000 by parliament in 1855. A channel to the south of Banks Island in the Arctic was christened the ‘McClure Strait’ in his honour. He subsequently handed over his journals of the expedition to Capt. Sherard Osborn, RN, who edited an account of the voyage, published in 1856 as The discovery of the north-west passage by HMS Investigator, which ran to several editions.
In 1856 McClure was given command of HMS Esk on the Pacific station. He served during the second China war (1857–60) and commanded a battalion of the naval brigade during the capture of Canton (January 1858). Created CB in May 1859, he was promoted to rear-admiral in March 1867. He married (1869) Ada Tudor; they had no children. In May 1873 he was promoted to vice-admiral on the retired list. He died (17 October 1873) in Duke St., St James's, London, and was buried in Kensal Green cemetery. Another version of his Arctic expeditions, Voyages, was published in 1884. A portrait of McClure, painted by Stephen Pearce, is in the collection of the National Portrait Gallery, London.