Thomas Barnes, the son of a lawyer, was born in Tenterden, Kent on 11th September 1785. He was educated at Christ's Hospital and Pembroke College, Cambridge. After obtaining a degree in 1808 he moved to London where he intended to become a lawyer. However, after becoming friends with a group of writers that included William Hazlitt, Henry Brougham, Lord Byron, Leigh Hunt and Charles Lamb, Barnes decided to become a journalist.
In 1809, Barnes met John Walter II, the owner of The Times. Barnes began contributing articles on legal matters but later that year became the newspaper's drama critic. The following year Dr. John Stoddart, the editor of The Times, appointed Barnes as the newspaper's parliamentary correspondent.
In 1817, Stoddart retired and Thomas Barnes became the new editor of The Times. When Barnes took over the newspaper it was selling around 7,000 copies a day and was failing to make a profit. John Walter II still held most of the shares in The Times, but by 1819 Barnes had sought and obtained full control over the editorial content of the newspaper.
Barnes supported the moderate reforms being suggested by his friends, John Hobhouse and Henry Brougham in the House of Commons. However, he was a strong opponent of radicals who favoured universal suffrage. In the summer of 1819, editorials in The Times denounced the activities of radicals such as Henry Orator Hunt and Major John Cartwright. Barnes criticised radicals for holding public meetings on parliamentary reform but warned the government not to try and suppress the movement by force. Barnes wrote that "last Monday we concluded an article which severely blamed Hunt as a moral agent, by expressing an anxious hope that no person would so conduct themselves as to share with that brawler the reproach of any evil consequences which might follow the assemblage of so large a body of discontented labourers."
One of Barnes' new innovations was to send staff reporters to cover political meetings. He decided that John Tyas should cover the parliamentary reform meeting at St. Peter's Field. Tyas was chosen because according to Barnes, he "was nephew to an individual of great respectability in the town of Manchester". Barnes was also convinced that Tyas was unlikely to write a sympathetic report on Henry Orator Hunt and the other radical speakers. Barnes wrote: "as far as we can judge from his preceding conduct towards this journal, (Tyas) is about as much a Jacobin, or friend of Jacobins, as is Lord Liverpool himself."
John Tyas and the other journalists at the meeting were positioned on the platform with the speakers. The soldiers assumed the journalists on the platform were sympathetic to the radicals. As a result, John Tyas was arrested with the speakers when the meeting was broken up.
Thomas Barnes was furious when he heard John Tyas had been arrested. As John Tyas was unable to send his report, The Times published an account written by John Edward Taylor, a journalist who worked for the Manchester Gazette. Although Taylor was not a radical, he was outraged by the Peterloo Massacre and the article was very critical of the authorities.
After John Tyas was released from prison, his full account of the events was published in The Times on 19th August. The Times mounted a campaign against the action of the magistrates at St. Peter's Field. In one editorial the newspaper told its readers "a hundred of the King's unarmed subjects have been sabred by a body of cavalry in the streets of a town of which most of them were inhabitants, and in the presence of those Magistrates whose sworn duty it is to protect and preserve the life of the meanest Englishmen." As these comments came from an establishment newspaper, the authorities found this criticism particularly damaging.
After the Peterloo Massacre Barnes became a more committed supporter of parliamentary reform. In 1830 Barnes and The Times supported Lord Grey and his government's attempt to extend the franchise. Barnes worked very closely with one of Grey's ministers, Henry Brougham. Barnes and Brougham saw a great deal of each other and most mornings had breakfast together. This close relationship upset the Tories and they complained that Henry Brougham was the real editor of The Times.
Thomas Barnes was now a committed supporter of parliamentary reform. Almost daily The Times urged the Whig government to take action. The views of Barnes had a great influence on public opinion. The government tax on newspapers meant that its price of 7d. made it too expensive for most people to buy. However, copies were available in reading rooms. In 1831 the St. James's Chronicle claimed that "for every one copy of The Times that is purchased for the usual purposes, nine we venture to say are purchased to be lent to the wretched characters who, being miserable, look to political changes for an amelioration of their condition."
In Parliament the Tories complained about The Times campaign. In a debate that took place in the House of Commons on 7th March, 1832, Sir Robert Peel argued that The Times was the "principal and most powerful advocate of Reform" in Britain. After the 1832 Reform Act was passed The Times called it the "greatest event of modern history."
In 1834 a group of Whigs purchased control of the Morning Chronicle. Barnes disagreed with the way the Morning Chronicle gave "slavish support to the government". Barnes had talks with the leaders of the Conservative Party and after they had agreed that they would not attempt to interfere with reforms introduced by the Whigs, such as the 1832 Reform Act and the Tithe Act, he agreed that the newspaper would became a supporter of Sir Robert Peel and his new government.
Under Thomas Barnes' editorship, sales of The Times continued to grow. For example, the issue of 11th February, 1839, that contained an account of Queen Victoria's plans to marry, sold 30,000 copies. Thomas Barnes remained editor of the newspaper until his death on 7th May 1841.