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. Ultimately, Cameron stepped down as premier that July, on the election of Theresa May as Conservative Party leader and Prime Minister. 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 (Bartons, and Tackley and Wooton) 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. Members of Parliament Elections Elections in the 2020s Elections in the 2010s : Elections in the 2000s : : Elections in the 1990s Elections in