In the late 19th century, the Bampton East petty sessional division, with Witney at its heart, formed one part of the Woodstock constituency. Until 1974, much of the seat remained as part of the Woodstock and latterly Banbury constituency. From 1974 to 1983, the area was included in the Mid Oxfordshire seat along with parts of Bullingdon and Ploughley. Since 1983, Witney has been a full parliamentary seat in its own right and comprises the whole of the District of West Oxfordshire with surrounding villages attached until 1997. Carterton is the second largest populated town with 14,000 and is situated alongside RAF Brize Norton which is vital to the local economy, being one of the largest and busiest Royal Air Force stations in the country. The constituency's first MP was Douglas Hurd, who served as a cabinet minister under both Margaret Thatcher and John Major, and retired in 1997. Hurd was succeeded by Shaun Woodward at the 1997 general election. However, Woodward defected to the Labour Party in 1999, and Witney unexpectedly had a Labour MP. Woodward chose not to stand in Witney as a Labour candidate and moved to the Labour safe seat of St Helens South instead, following the practice of Alan Howarth in 1997. At the 2001 general election, David Cameron was elected as MP for Witney. Cameron was re-elected to a fourth term as MP for the constituency at the 2015 general election with a majority of 25,155, the highest in his political career; on that occasion his Conservative Party won a surprise overall majority in the House of Commons, taking 330 seats to the opposition Labour Party's 232. However, on 24 June 2016, Cameron announced that he would resign as Prime Minister by that October due to the outcome of the EU Referendum the previous day, in which 51.9% of voters supported leaving the EU. On 12 September 2016, it was announced that Cameron would resign as MP for Witney. This triggered a by-election, which was won by Robert Courts, also a Conservative, albeit with a significantly reduced majority. Before the 2019 general election, the Liberal Democrats and Green Party agreed not to run against each other as part of a "Unite to Remain" alliance. This led to Andrew Prosser, who had been selected as the Green Party's prospective candidate standing down.
Boundaries and boundary changes
1983–1997: The District of West Oxfordshire wards of Ascott and Shipton, Aston Bampton and Standlake, Bampton, Bladon and Cassington, Brize Norton and Curbridge, Burford, Carterton North, Carterton South, Chadlington, Charlbury, Chipping Norton, Clanfield and Shilton, Combe and Stonesfield, Ducklington, Enstone, Eynsham, Filkins and Langford, Finstock and Leafield, Freeland and Hanborough, Hailey, Kingham, Milton-under-Wychwood, Minster Lovell, North Leigh, Rollright, Stanton Harcourt, Witney East, Witney North, Witney South, Witney West, and Woodstock, and the District of Cherwell wards of Gosford, North West Kidlington, South East Kidlington, and Yarnton. The new constituency was largely formed from the majority of the abolished County Constituency of Mid-Oxon, including the settlements of Witney, Carterton, Woodstock and Kidlington. Chipping Norton and surrounding rural areas were transferred from the Banbury constituency. 1997–2010: The District of West Oxfordshire, and the District of Cherwell ward of Yarnton. The remaining two wards of the District of West Oxfordshire were transferred from Banbury. Kidlington transferred to Oxford West and Abingdon. 2010–present: The District of West Oxfordshire. As part of the Fifth Periodic Review of Westminster constituencies the Boundary Commission reported in 2004 that the seat of Witney could be composed from the entire district of West Oxfordshire, with the District of Cherwell ward of Yarnton being transferred to Oxford West and Abingdon.
