Dictionary of National Biography, 1885-1900/Addington, Henry Unwin
ADDINGTON, HENRY UNWIN (1790–1870), permanent under-secretary for foreign affairs, was the son of the Right Hon. John Addington, brother of the first Lord Sidmouth, and was born 24 March 1790. He was educated at Winchester school, and entered the Foreign Office in January 1807. After serving on various diplomatic missions he in 1814 became secretary of legation to Switzerland, and was afterwards transferred successively to Copenhagen and Washington. Though he retired from active service on a pension in 1826, his experience was taken advantage of on several occasions as a plenipotentiary: in 1826 during the negotiations with the United States in London, in 1828 at the diet of Frankfort, and from 1829 to 1833 at Madrid. From 1842 to 1854 he acted as permanent under-secretary of state for foreign affairs, and on his retirement from that office he was sworn a privy councillor. He died 6 March 1870.
[Times, 8 March 1870.]