Houstoun was the grandson of Alexander Houstoun (d.1777) founder of the Glasgow merchant firm trading with the West Indies. He served as lieutenant-governor of Grenada until his resignation in April 1802, whence his sobriquet of ‘Governor Houstoun’.
Houstoun, who had Melville’s approbation, supported government. He voted with them throughout the Scheldt debates, January-March 1810, and against the release of the radical agitator Gale Jones, 16 Apr.; on the Regency question, 1 Jan. 1811; against sinecure reform. 24 Feb., 4 May 1812, and against a ‘stronger’ administration, 21 May. On 5 and 8 May 1811 he presented petitions from distressed Scottish cotton manufacturers and on 5 June was named to the select committee on the subject. Perceval suggested him, rather than Lord Archibald Hamilton, for the finance committee, 9 Jan. 1812, but by a compromise neither was adopted. He presented his constituents’ petitions for free trade with the Orient, 6 Feb., 25, 26 Mar. 1812.
Before the election of 1812, Houstoun renewed his agreement with Archibald Campbell, reserving Glasgow for the Parliament after next. It appears that he was to have been offered a Treasury borough for £3,000, but nothing came of it.
