1885–1918: The Sessional Divisions of Horsham, Midhurst, Petworth, the civil parish of Crawley.
1945–1950: The Urban Districts of Horsham, Shoreham-by-Sea, Southwick, the Rural Districts of Chanctonbury and Horsham.
1950–1974: The Urban District of Horsham, the Rural Districts of Horsham, Midhurst, Petworth.
1983–1997: The District of Horsham.
1997–2010: The District of Horsham wards of Billingshurst, Broadbridge Heath, Cowfold, Denne, Forest, Holbrook, Itchingfield and Shipley, Nuthurst, Riverside, Roffey North, Rudgwick, Rusper, Slinfold, Southwater, Trafalgar, Warnham, the District of Mid Sussex wards of Balcombe, Copthorne and Worth, Crawley Down, Slaugham, Turners Hill, the District of Chichester wards of Plaistow and Wisborough Green.
2010–2024: The District of Horsham wards of Billingshurst and Shipley, Broadbridge Heath, Denne, Forest, Holbrook East, Holbrook West, Horsham Park, Itchingfield, Slinfold and Warnham, Nuthurst, Roffey North, Roffey South, Rudgwick, Rusper and Colgate, Southwater, and Trafalgar, and the District of Mid Sussex wards of Ardingly and Balcombe, Copthorne and Worth, and Crawley Down and Turners Hill.
The District of Horsham wards of: Billingshurst; Broadbridge Heath; Colgate & Rusper; Cowfold, Shermanbury & West Grinstead; Denne; Forest; Holbrook East; Holbrook West; Itchingfield, Slinfold & Warnham; Nuthurst & Lower Beeding; Roffey North; Roffey South; Rudgwick; Southwater North; Southwater South & Shipley; Trafalgar.[2]
The electorate was reduced to bring it within the permitted range by transferring rural wards to the east and south of Crawley to the newly created constituency of East Grinstead and Uckfield. The Cowfold, Shermanbury & West Grinstead ward was added from Arundel and South Downs.
Horsham has existed as a constituency for three distinct periods. It first sent members to Parliament in 1295. However, the constituency was abolished in 1918 to make way for Horsham and Worthing. In 1945 the constituency was recreated, until 1974 when Horsham and Crawley was created. In 1983 the constituency of Horsham was again created and has existed since.
Until the 1885, the seat was constituted as a Parliamentary Borough, sending two MPs (burgesses) to the House of Commons up to 1832, when its representation was reduced to one member by the Reform Act 1832. Under the Redistribution of Seats Act 1885, the parliamentary borough was abolished, but the name of Horsham was retained as a division of the parliamentary county of Sussex, covering northern areas of what is now West Sussex. Further to the Representation of the People Act 1918, the seat was abolished and largely absorbed into the new constituency of Horsham and Worthing, which also incorporated the coastal towns of Worthing, Shoreham-by-Sea and Southwick – previously part of the Lewes division of Sussex.
By the 1940s, the Horsham and Worthing seat had an electorate of over 100,000 and, for the 1945 general election, the seat was divided in two with the re-establishment of Horsham and the creation of a separate constituency of Worthing. For the following election in 1950, Horsham lost Shoreham and Southwick to the new seat of Arundel and Shoreham. Under the Second Periodic Review of Westminster constituencies which came into effect for the February 1974 election, the seat was renamed Horsham and Crawley to reflect the growing proportion of the electorate coming from the new town of Crawley.
The constituency (including the two versions under other names) was held by members of the Conservative Party from 1880 to 2024, when it was taken by the Liberal Democrats at the 4th July general election.[3]Edward Turnour held the seat for 47 years from a 1904 byelection until the 1951 general election, which included the whole period of Horsham and Worthing's existence. Similarly, Peter Hordern held the seat for 33 years from 1964 to 1997, including the whole period of Horsham and Crawley's existence.
Its Member of Parliament (MP) was Francis Maude between 1997 and 2015; followed by fellow Conservative Jeremy Quin until 2024 when the seat was taken from Quin by John Milne of the Liberal Democrats, making it the first time since 1876 that a non-Conservative Party candidate has won the seat. The Liberal Democrats (or one of its predecessors, the Social Democatic Party) had come second to the Conservatives at every general election from 1983 to 2019, except 2015 (UKIP) and 2017 (Labour).
This constituency underwent boundary changes between the 1992 and 1997 general elections and thus change in share of vote is based on a notional calculation.
Both candidates received the same number of votes, and both were declared elected, with petitions lodged against both. However, on 3 May 1869, Aldridge withdrew his claim to the seat allowing Hurst to be the sole MP.[41]
Held due to the 1847 general election result being declared void on petition, due to treating, on 23 March 1848.[43] After a further petition arising from the by-election, Vesey-Fitzgerald was declared unduly elected, due to bribery and treating by both him and his agents, and Fitzalan-Howard was declared elected on 8 September 1848.[44]
^Reform UK withdrew their support for Miller on 7 June 2024, after nominations closed the same day, so he still appeared as the Reform UK candidate on the ballot paper.[18]
^After the 1868 election, petitions were lodged against both candidates and Aldridge chose not to defend his claim so Hurst was declared elected in 1869