Zac Goldsmith Conservative Sarah Olney Liberal Democrats On 1 December 2016, a by-election was held in the UK parliamentary constituency of Richmond Park.

[1][2] It was triggered by the resignation of the Conservative Member of Parliament Zac Goldsmith on 25 October 2016 over the Government's proposal for a third runway at the nearby Heathrow Airport.

When the May ministry announced on 25 October 2016 that the government would support a third runway at Heathrow, Goldsmith resigned his seat.

[4][5] He was described as an "Independent Conservative",[6] although that ballot paper description has not been permitted since the Registration of Political Parties Act 1998 came into force.

[13] A leader for the Evening Standard described the Conservative Prime Minister, Theresa May, as having "endorsed" Goldsmith.

[15] The Liberal Democrats confirmed Sarah Olney, who was selected to fight the constituency in the event of a snap election, as their candidate for the by-election on 30 October.

She lived locally in North Kingston and worked as an accountant at the National Physical Laboratory in Teddington.

[25] Wolmar defeated four candidates for the nomination: Ellie Cumbo, a researcher at the General Council of the Bar of England and Wales; Barnaby Marder, a local activist backed by Momentum; Sachin Patel, a supermarket manager and Union of Shop, Distributive and Allied Workers representative who contested the seat for Labour at the 2015 election; and Jessica Toale, who had been an advisor to Ivan Lewis MP.

[1][31] The Women's Equality Party did not stand a candidate and backed Olney, in opposition to what they described as Goldsmith's record of "racist" campaigning.

They campaigned on an anti-Brexit position, noting Goldsmith's own support for Brexit whereas the area strongly voted for Remain in the 2016 EU membership referendum.

[43] The Liberal Democrat campaign started quickly, with leader Tim Farron first visiting the constituency on 26 October.

[47] Nick Clegg, the former Liberal Democrat leader and Deputy Prime Minister, launched Olney's campaign on 31 October/1 November, stressing the party's opposition to Heathrow.

The results in the EU referendum on 23 June 2016 were reported by local authority, and, as the constituency consists of parts of two local authorities, the London Borough of Richmond upon Thames and the Royal Borough of Kingston upon Thames, the exact referendum vote in Richmond Park is not known.

However, Chris Hanretty, a Reader in Politics at the University of East Anglia, estimated through a demographic model that Richmond Park had one of the dozen lowest 'Leave' votes in the entire country.