entered parliament at the 1868 general election as Member of Parliament (MP) for Mid-Lincolnshire. He represented this constituency until it was replaced under the Redistribution of Seats Act 1885. In the 1885 general election he was returned to parliament for the new Sleaford division which he held until his defeat at the 1906 general election. He was a devoted follower and admirer of Benjamin Disraeli, and they struck up a close friendship. Despite their political differences, Chaplin also retained the friendship and respect of the Liberal prime minister, William Ewart Gladstone, until the end of his life. On 29 April 1869 Chaplin delivered his maiden speech on the Irish Church Bill, which disestablished the Church of Ireland. During the summer of 1875, Chaplin remained in London rather than attend Brighton races, in order to assist Disraeli in supporting the Merchant Shipping Bill against the opposition of Samuel Plimsoll. Disraeli wrote to Lady Bradford on 30 July: "He has never left my side, and his aid has been invaluable. He is a natural orator and a debater too. He is the best speaker in the House of Commons or will be. Mark my words". Chaplin also supported Disraeli's government against Liberal opposition during the debates on the Royal Titles Bill, which conferred on Queen Victoria the title "Empress of India". Chaplin was a lifelong advocate of protectionism, being in this respect the most prominent inheritor of the views of Lord George Bentinck; his daughter Edith said he was "born a Protectionist, and to the end he remained convinced that Tariff Reform was the only measure which could restore a satisfactory means of livelihood to the English farmer". He was a member of the Royal Commission on the Depressed Condition of the Agricultural Interests (1879–1882) and opposed the Radicals' campaign to replace landlords with peasant proprietorship. The Royal Commission's final report blamed the agricultural depression on excessive foreign competition and the adoption of the gold standard, which had contributed to the decline in prices. Chaplin thereafter became an advocate of bimetallism. Chaplin was sworn of the Privy Council in 1885 and filled the office of Chancellor of the Duchy of Lancaster in Lord Salisbury's short ministry of 1885 to 1886. He opposed Gladstone's Irish Home Rule Bill of 1886, and when the Conservatives returned to power that year he turned down Salisbury's offer of the Department of Agriculture, which did not then