Clotworthy Upton was born in 1768, the illegitimate son of Clotworthy Upton, 1st Baron Templetown, and his eventual wife, Elizabeth Boughton. At the age of eleven, he joined the Royal Navy as servant to captain Richard Kempenfelt, aboard HMS Alexander. He passed his lieutenant's examination in 1790 but was unable to find employment within the service, and between 1791 - 1794 worked on merchant ships travelling to and from the Eastern World. One such journey, in 1792, was to Madras aboard the King George.^[1]

In January 1801, Upton returned to the Royal Navy as Master and Commander of HMS Zephyr.^[1] She had been fitted as a fireship was sent to the Baltic with a large force, under Admiral Sir Hyde Parker, to disrupt the league of armed neutrality. Because of the shoal waters around Copenhagen, Parker's larger ships were unable to get close enough to engage the anchored Danish fleet but Zephyr joined Horatio Nelson's squadron and was at the Battle of Copenhagen on 2 April.^[2] Zephyr was in a squadron of sloops and frigates, under the command of Edward Riou, that attacked the Danish vessels near the harbour mouth.^[3] Riou's force took heavy fire from the Trekroner batteries and withdrew when Parker gave the signal.^[4]

In celebration of the Peace of Amiens, a number of officers were given promotions, and Upton received the rank of Post Captain.^[1] Hostilities resumed in May 1803 and, in December 1804, Upton was given command on the 28-gun sixth-rate frigate, HMS Lapwing.^[5] In December 1805, he moved to HMS Camilla of 20 guns,^[6] then in March 1806, to HMS Aimable of 32 guns, in the North Sea.^[7] HMS Sybille in which Upton served from 1807 to 1813, was his longest command. In her, he took part in the second battle of Copenhagen.^[1] On 25 January 1808, Upton's Sibylle captured the 4-gun French privateer Grand Argus and on 16 August, the 16-gun brig-corvette Espiegle.^[8] In 1810, she took the 14-gun brig, Edouard.^[1]

Upton took command of HMS Junon in North America, in September 1813, and sailed in her for the Halifax Station.^[9] On 3 April 1814, while cruising with HMS Tenedos, Junon chased the USS Constitution into Marblehead, Massachusetts.^[1] The captain of Tenedos, Hyde Parker, wanted to follow but Upton ordered him to abandon the pursuit.^[1]

Upton's last command at sea was HMS Royal Oak which he joined in 1815, shortly before she was laid up in ordinary at Portsmouth.^[10] In 1818, Upton took the position of commissioner at the Royal Navy dockyard in Trincomalee.^[1]

Despite the marriage of his parents a year after his birth, Upton's illegitimacy could not be revoked and he was deprived of any legal claim on the family estate. He did however inherit from his father, who prior to his death in 1785, had set up a trust for all his children. Upton did not receive the family barony though, which passed to his brother John, the eldest surviving of the couple's three legitimate offspring.^[1]

Upton was married in 1805, at St Pancras Old Church, London, to Elizabeth Walton, whose father was a wealthy American merchant. They had one child, a daughter, Eliza Mary, who went on to marry a Scottish lord.^[1]

Upton died and was buried at sea, in 1822. He was on his way home from his appointment in Trincomalee where cholera had taken its toll on his fellow officers.^[1]

• Clowes, William Laird (1997) [1900]. The Royal Navy, A History from the Earliest Times to 1900, Volume IV. London: Chatham Publishing. ISBN 1-86176-013-2.
• Hore, Peter (2015). Nelson's Band of Brothers: Lives and Memorials. Barnsley.: Seaforth Publishing. ISBN 9781848327795.
• Winfield, Rif (2008). British Warships in the Age of Sail 1793–1817: Design, Construction, Careers and Fates. Barnsley: Seaforth. ISBN 978-1-86176-246-7.