Gibson was born on September 3, 1806 in Port of Spain, Trinidad and Tobago, where his father was serving as an officer in the army. He came of a Suffolk family. The family returned to England almost immediately after the younger Thomas’s birth, but the father died in May 1807 leaving his wife and son comfortably off and living in Theberton House.
Gibson was educated in Trinidad, in a school at Higham Hill also attended by Benjamin Disraeli, at Charterhouse, and at Trinity College, Cambridge, where he graduated in 1830.
In 1837 Gibson was elected to parliament as Conservative member for Ipswich, but resigned two years later, having adopted Liberal views, and became an ardent supporter of the free-trade movement. As one of Cobden's chief allies, he was elected to the House of Commons as Member of Parliament for Manchester in 1841, and from 1846 to 1848 he was Vice-President of the Board of Trade in Lord John Russell's ministry. Though defeated in Manchester in 1857, he found another seat for Ashton-under-Lyne, and sat in the cabinet under Lord Palmerston and then Russell from 1859 to 1866 as President of the Board of Trade.
In 1846 he was sworn of the Privy Council. As well as working on the commercial treaties, Milner Gibson campaigned for the removal of taxes on newspapers and newspaper advertising, and this was the cause with which contemporaries most associated him.
The first Parliamentary reform act in 1832 had created constituencies reflecting the distribution of population and had given the vote to all males owning a significant amount of property. It was a radical cause to extend the vote to a wider segment of the male population, and this was achieved by the Second Reform Act of 1867. Thomas was speaking in favour of this extension as early as 1854, but it only made sense if the new voters, many not at all rich, had the knowledge to use their vote prudently. Taxes on newspapers and newspaper advertising raised the price of newspapers beyond their reach, and so Thomas had become president of the Association for the Repeal of Taxes on Knowledge in 1850.
He led the campaign for the abolition of these taxes and in 1853 defeated a government motion on advertising duties. In government he concluded an alliance with Gladstone, the Chancellor of the Exchequer, who had to make good the revenue lost once these taxes were abolished. Gladstone had a strong Radical streak and was anyway sympathetic, but Thomas strongly supported the defence cuts Gladstone imposed, and as a result Gladstone had abolished all taxes on newspapers by October 1861. Mass circulation newspapers became a commercial possibility opening the way for the tabloid press. This was the last significant act of Thomas’s political career: he lost his seat in the General Election of 1868 and then declined an invitation to stand at Norwich in 1869. He was offered the governorship of Mauritius and a knighthood but declined both, accepting a pension of £2000 p. a. instead. He died at Algiers on board Resolute on 25 February 1884 and his body was brought back to Theberton for burial.
Milner Gibson was a sportsman and a typical man of the world, who enjoyed life and behaved liberally to those connected with him.
Milner Gibson married Arethusa Susannah, daughter of Revd. Sir Thomas Gery Cullum of Hardwick House, Suffolk, in 1832. They resided at Theberton House, Suffolk. Gibson also had a relationship with Susannah Bowles, a servant girl. Their son, Thomas Gibson Bowles, became a noted publisher and was the maternal grandfather of the Mitford sisters.
