A Conservative of ‘decided and independent character’, Wyndham was returned for Cumberland West in 1860, holding his seat for a quarter of a century.
In August 1860 Wyndham was brought forward on his family’s interest for the vacancy at Cumberland West, following the death of his uncle. Facing accusations that he was ‘young and untried’, he introduced himself to the constituency with a speech calling for non-intervention in foreign affairs, as ‘any other course would only embroil us with old allies, and do little for our new friends’. He was also unequivocally opposed to the ballot, describing it as ‘a cowardly, sneaking and un-English measure, very unfair to the non-electors of the country’.
In Parliament, however, Wyndham, after a tentative start, proved to be an indefatigable presence as Conservative member for Cumberland West. He attended frequently, spoke regularly on a range of issues, and, in his second Parliament, developed positions which were in advance of his own party, which he was not afraid to criticise. In his first Parliament, though, he followed Disraeli into the division lobby on most major issues, including his censure of the government’s handling of the Danish war, 8 July 1864, and he voted against Locke King’s county franchise bill, 13 Mar. 1861, and Baines’ borough franchise bill, 10 Apr. 1861. In a key debate on the American civil war, he advocated the recognition of the Southern Confederacy, and claimed that ‘the men in the Northern State ... were engaged in a hopeless contest’, 30 June 1863. A dogged questioner of ministers, he proposed to the secretary of state for war that recruitment for the army could be improved by allowing soldiers who had served for eighteen years to be appointed to positions in the civil service, 20 Mar. 1865, and informed the president of the board of trade that the government needed to intervene in the question of railway safety, 4 July 1865, but both suggestions were rebuffed. He also took a keen interest in the 1861 Salmon Fisheries Act, insisting that the legislation needed amending, 29 Apr. 1864. He served on the subsequent select committee.
Following his unopposed return at the 1865 general election, Wyndham focused much of his efforts on attempting to steer his mines assessment bill through Parliament.
Wyndham’s interventions in debate in this period reflected his progressive opinions. Although he had initially voted against the tests abolition (Oxford) bill, 16 Mar. 1864, he subsequently declared that, after further inquiry, he ‘could not believe that the religious teaching given in the colleges would be interfered with’, and divided, against his party, in favour of the bill, 13 June 1866. Wyndham also showed marked independence in his votes on the major clauses of the representation of the people bill, dividing with Gladstone for a reduction of the copyhold franchise, 20 May 1867, and supporting John Stuart Mill’s amendment for the enfranchisement of women, 20 May 1867. Significantly, having voted against Gladstone’s resolution on the Irish Church, 3 Apr. 1868, he was noticeably critical of the Disraeli ministry’s decision to stay in power following its defeat on the issue. Arguing that ‘the government of the country and the direction of legislation on all important questions no longer remained in the hands of the government’, he portrayed the ministry as a ‘weak man’, and warned Disraeli that ‘there were some at least of his supporters who would refuse to be dragged through the mud, in order to enable the government to remain’, 21 May 1868.
Wyndham continued to sit for Cumberland West until the constituency’s abolition in 1885. On most issues, he remained loyal to the Conservatives, delivering lectures and speeches against Gladstone’s ‘Bulgarian Atrocities’ campaign and joining the council of the Fair Trade League. However, on religious questions, he remained in advance of his party, and supported Charles Bradlaugh’s admission to the Commons.