Preston is a constituency^{[n 1]} represented in the House of Commons of the UK Parliament since 2000 by Sir Mark Hendrick, a member of the Labour Party and Co-operative Party.^{[n 2]}

1295–1950

The seat was created for the Model Parliament and sent members until at least 1331 until a new (possibly confirmatory) grant of two members to Westminster followed. From 1529 extending unusually beyond the 19th century until the 1950 general election the seat had two-member representation. Party divisions tended to run stronger after 1931 before which two different parties' candidates frequently came first and second at elections under the bloc vote system.

In 1929, a recently elected Liberal, Sir William Jowitt decided to join the Labour Party and called for a by-election (which implies a single vacancy) to support this change of party, which he won, to take up for two years the position of Attorney General of England and Wales as part of the Government. He became the highest judge during the Attlee Ministry, the Lord High Chancellor of Great Britain and Speaker of the House of Lords under a then hereditary-dominated House leading to a Conservative majority. Consequently, he was selected to be elevated to a peerage as 1st Earl Jowitt. With no sons, he was to be the last Earl and wrote the Dictionary of English Law.

1950–1983

Preston was abolished as a constituency by the House of Commons (Redistribution of Seats) Act 1949 being replaced by Preston North and Preston South constituencies.

1983–present

The representatives since the seat's revival after 33 years of being split between (larger area) North and South seats have all been members of the Labour Party.

The member from 1987 to 2000 was Audrey Wise, a member of the Socialist Campaign Group and reformer of maternity healthcare in opposition on the Select Committee.

1832–1868: The old borough of Preston, and the township of Fishwick.^[2]

1868–1885: The existing parliamentary borough, excluding such part (if any) as lies on the south side of the River Ribble.^[3]

1885–1918: The existing parliamentary borough, so much of the municipal borough of Preston as was not already included in the parliamentary borough, so much of the parish of Lea, Ashton, Ingol, and Cottam, and of the parish of Penwortham, as were added to the municipal borough of Preston on 1 June 1889 by the Ribble Navigation and Preston Dock Act 1883, and the local government district of Fulwood.^[4]

1983–1997: The Borough of Preston wards of Ashton, Avenham, Brookfield, Central, Deepdale, Fishwick, Ingol, Larches, Moorbrook, Park, Ribbleton, St John's, St Matthew's, and Tulketh.

1997–2010: The Borough of Preston wards of Ashton, Avenham, Brookfield, Central, Deepdale, Fishwick, Larches, Moor Park, Ribbleton, Riversway, St Matthew's, and Tulketh, and the Borough of South Ribble wards of Bamber Bridge Central, Bamber Bridge South, and Walton-le-Dale.

2010–present: The City of Preston wards of Ashton, Brookfield, Deepdale, Fishwick, Ingol, Larches, Moor Park, Ribbleton, Riversway, St George's, St Matthew's, Town Centre, Tulketh, and University.

The composition of the Preston constituency was confirmed in time for the 2010 United Kingdom general election as part of the Fifth Periodic Review of Westminster constituencies. While it previously crossed the River Ribble to include Bamber Bridge and Walton-le-Dale from South Ribble District, the seat now falls within the City boundaries.

Representatives have sat in Parliament for Preston for nearly 800 years, the first recorded names being Willielmus fil' Pauli and Adam Russel. Prior to being reformed as "Preston" in 1983, the former Preston North and Preston South seats were amongst the most marginal in the country - in 1979, Conservative Robert Atkins won Preston North by 29 votes.

With the suburban, middle class former Fulwood Urban District area within Ribble Valley (and from 2010 Wyre and Preston North), the southern portion has awarded MPs with much healthier and secure majorities. Almost all of Preston's representatives from 1915 to 1950, and since its recreation as a single constituency in 1983, have been Labour candidates.

Between 1918 and 1949, the two-seat constituency of Preston was formed by the County Borough of Preston and the Urban District of Fulwood. In 1997, Audrey Wise secured a majority of over 18,000. The collapse of the Conservative vote - 10 percentage points down from 1992 - was firmly with the pattern of the Tory fortunes in that year.

The death of Audrey Wise in 2000 triggered a by-election. At that Preston by-election, Mark Hendrick, former Member of the European Parliament (MEP) for the Lancashire Central constituency with Preston at its heart, secured a victory with a 4,400 majority. The surprise of the night was the result of the fledgling Socialist Alliance, for whom Terry Cartright saved his deposit.

Less than a year later, the 2001 general election returned Mark Hendrick with a much healthier 12,200 majority, up against South Ribble councillor Graham O'Hare for the Conservatives and the then local Liberal Democrat leader Bill Chadwick. In real terms, all three main parties lost support from 1997 - Labour down by over 8,000 votes, Conservatives reduced by over 2,200 and Lib Dems 2,300 lower. One notable candidate in 2001 was David Braid, also a candidate in a number of other seats that year, who had been the "Battle for Britain" candidate in the previous year's by-election.

The 2005 general election was notable for the changes in share of the vote of the minor parties. The first ever Respect candidate, local councillor Michael Lavalette, firmly saved his deposit with nearly 7% of the vote. The Liberal Democrats had chosen former Conservative County Councillor William Parkinson, and had their best result since 1997. Fiona Bryce for the Conservatives, remained in second place seeing her share of the vote remain stable despite the United Kingdom Independence Party (UKIP) polling over 1,000 votes. Mark Hendrick secured another term as MP, although his vote total was 3,000 less than 2001 and 12,000 less than Audrey Wise in 1997.

Labour continued to represent Preston at the elections of 2010, 2015, and 2017. Whilst Mark Hendrick secured less than 50% of the votes cast in 2010, the first time this has occurred at a Preston election since 1983, subsequent results had much stronger Labour majorities. Second place went back to the Conservative Party, regaining from the Liberal Democrats who took second place for the first time in 2010.

• List of parliamentary constituencies in Lancashire
• 1915 Preston by-election
• 1929 Preston by-election
• 1936 Preston by-election
• 1940 Preston by-election
• 2000 Preston by-election