Henry Addington, first Viscount Sidmouth (1757-1844), Speaker, Prime Minister, and afterwards the Home Secretary through whom the Island's business passed.

He was called to the chair of the House of Commons in 1789 on the motion of the Master of the Rolls, carried against Mr Grey's tellers by two hundred and fifteen votes to a hundred and forty-two, and he was re-elected Speaker in 1796. He left the chair in February 1801 to become Prime Minister, and the House voted him its thanks in the strongest terms. He was afterwards created Viscount Sidmouth and introduced to the Lords with the accustomed formalities, his supporters being the Viscounts Wentworth and Sydney.

His Manx significance is the Home Office. As Secretary of State he was the minister to whom the Lieutenant-Governor and the Island's officers wrote, and the calendars of the HO 98 series are full of it. Lord Ellenborough forwarded him a letter from John Christian of Fort Ann wishing to be considered for the Attorney-Generalship in December 1812, and Sidmouth answered privately that it was not possible. Lieutenant-Governor Smelt sent him Deemster Gawne's application to be paid for extra work in 1818, and Gawne wrote to him directly on the same matter. John Cosnahan asked him whether his son John Finch Cosnahan might collect his commission as Deemster. On the customs questions in which the Duke of Atholl had become interested by the Act, Sidmouth's opinion is stated to have concurred pretty nearly with Lord Ellenborough's.