Middlesbrough is a parliamentary constituency in the United Kingdom, recreated in 1974, and represented since 2012 in the House of Commons of the UK Parliament by Andy McDonald from the Labour Party. An earlier version of the seat existed between 1868 and 1918. History First creation Parliament created this seat under the Representation of the People Act 1867 for the general election the next year, however the population expanded so was split into east/west areas in 1918. From 1950 until 1974, given intervening expansion of suburbs across the country, the Metropolitan Borough of Thornaby closer to Stockton on Tees was included in the Middlesbrough West constituency. Thornaby was enveloped into Teesside County Borough from 1974 and has not been part of the associated seats otherwise. Second creation – current The seat was recreated on similar boundaries to those which existed immediately before 1918. Results of the winning party The 2015 result made the seat the 36-safest of Labour's 232 seats by percentage of majority. Since the constituency's re-creation in 1974, Middlesbrough has elected the Labour Party's candidate as its MP. In areas formerly part of Middlesbrough East, the MP has been Labour since 1950. Middlesbrough West took in rural and semi-rural areas outside the borough to the west, and was a marginal seat passing three times between the two largest parties after the Second World War, but a Liberal stronghold from 1918 until 1945; former soldier and iron and steel merchant Trevelyan Thomson ran unopposed at the polls for re-election in 1924. Opposition parties The 2012 by-election and 2015 general election saw UKIP finish second. The Liberal Democrats fielded second-placed candidates in 2005 and 2010. The Conservatives did in all elections between the seat's revival and 2001, and returned to second place in 2017. The Green Party outpolled the Liberal Democrats in 2015 in a field of five parties' candidates standing — the two parties failed to achieve 5% of votes cast leading them to forfeit their deposits. Turnout Turnout has ranged between 70.1% in 1987 and 48.8% in 2005. Boundaries 1868–1885: The township of Linthorpe, and so much of the townships of Middlesbrough, Ormesby, and Eston as lie to the north of the road leading from Eston towards Yarm. 1885–1918: The existing parliamentary borough, and so much of the municipal borough of Middlesbrough as was not already included in the parliamentary borough. 1974–1983: The County Borough of Teesside wards