William Alexander Mackinnon DL JP FRS (2 August 1789 – 30 April 1870) was a British politician and a colonisation commissioner for South Australia. Early life He was born in Broadstairs, Kent in 1789 and educated at St John's College, Cambridge. He was the eldest son of William Mackinnon of Antigua and Harriet (née Frye) Mackinnon, a daughter of Francis Frye of Antigua. This made him brother of Lieutenant Colonel Daniel Mackinnon and brother-in-law of John Molesworth. He was a beneficiary of slavery in the British West Indies. He succeeded in 1809 as the 33rd Chief of the Clan Mackinnon. Career A Whig, he was Member of Parliament (MP) for Dunwich from 1819 to 1820, for Lymington from 1831 to 1832 and from 1835 to 1852, and for Rye from 1853 to 1865. He was a signatory of the third (of four) annual report of the Colonisation Commissioners of South Australia. At the 1852 general election he was defeated in Lymington, but his son William had been elected in Rye. However, a petition was lodged against the younger Mackinnon's election, and in May 1853 it was declared void. The elder Mackinnon successfully contested the resulting by-election on 23 May 1853. On his retirement in 1865 the seat was taken by his son, Lauchlan Bellingham. Again, treating was alleged. He was a J.P. and Deputy Lieutenant of Middlesex. Some of his parliamentary work concerned animal welfare and in 1858 he chaired the AGM of the RSPCA, having been appointed vice chair in 1837. He was elected a Fellow of the Royal Society in 1827, submitting a paper on the absorption of atmospheric moisture by the state of chalk and limestone. He was also invested as a fellow of the Society of Antiquaries. He was chairman of the Furness Iron and Steel Co at its inauguration in 1866. His three sons were also shareholders. He was a director of the Elan Valley Railway He wrote three books, "Thoughts on the currency question", "Public Opinion" and "The history of civilisation" Personal life Mackinnon was married to Emma Mary Palmer, daughter of Joseph Palmer, of Palmerstown, County Mayo and Rush House, County Dublin. Before her death in November 1835, they had three sons and three daughters, including: Emma Mary Mackinnon (1811–1891), who married Antoine Alfred Agénor, 20th Duke of Gramont, who was Foreign minister for the French Second Empire, and who instigated contact with