Colonel Robert Cotton St John Trefusis, 18th Baron Clinton was a British Army officer and courtier. He served as an aide de camp to Lord Wellington during the Peninsular War, and in August 1812 conveyed Wellington's dispatches on the battle of Salamanca to Britain, receiving two promotions in the space of a week. On half-pay from 1814, Trefusis became an aide de camp to George IV in 1825 and a Lord of the Bedchamber two years later. He died near Florence, Italy, in 1832 while attempting to recuperate from an illness. With no children having eventuated from his marriage, his brother Charles inherited the barony.
