The son of the seventeenth baron (d. 1797); he was educated at Harrow, enlisted in 1803, and fought in the Peninsular War under Wellington. He died in Florence, childless and intestate.

REFERENCES TO Robert Cotton St. John Trefusis, 18th Lord Clinton:

Lady Holland to John Whishart, 11 July 1814 in The “Pope” of Holland House: Selections from the Correspondence of John Whishaw and his Friends 1813-1840 (London: T. Fisher Unwin, 1906)

John Allen to John Whishart, 19 August 1814 in The “Pope” of Holland House: Selections from the Correspondence of John Whishaw and his Friends 1813-1840 (London: T. Fisher Unwin, 1906)

Thomas Creevey to Elizabeth Ord, 11 February 1821 in The Creevey Papers: A Selection from the Correspondence & Diaries of the late Thomas Creevey, M.P. (London: John Murray, 1903)