[3] The Liberal Democrat candidate, Sarah Green, won the by-election with 56.7% of the vote and a swing from the Conservatives of 25.2%.

The estimated turnout of 83.6% was the highest figure for any constituency in the UK, with only Gibraltar reporting a higher percentage.

[11] On 9 May, former Conservative MP Phillip Lee, who joined the Liberal Democrats before the 2019 election, urged the Labour and Green parties not to stand candidates in the by-election to avoid vote splitting.

[24] Writing in The Guardian on 14 May, columnist Polly Toynbee also called for an electoral alliance of the Liberal Democrats, Labour and the Green Party to beat the Conservatives.

On 12 May, the writ for the by-election was moved in the House of Commons by Government Chief Whip Mark Spencer.

[30][non-primary source needed] The results shocked the political landscape, as politicians and pundits had predicted a Conservative win in the run-up to the by-election.