Voting will take place on Thursday 20 July, the week after the Great Yorkshire Show.

The former Tory cabinet minister won the seat in 2019 with 60 per cent of vote and a majority of over 20,000.

Labour came second with 25 per cent of the vote, 35 percentage points behind the Tories.

Proposed boundary review changes will not take effect until the next general election.

Analysis by The Yorkshire Post found that the seat will become more marginal in next year’s election, with a significant chunk of Labour-voting Leeds voters set to be included in the new constituency.

Three parties have confirmed their candidates for the election so far.

Conservatives - Claire Holmes

The Tories have selected Claire Holmes, a local councillor for the East Riding, for their candidate.

She told The Yorkshire Post in an interview following her selection that she wanted to protect green spaces from inappropriate housing.

The Conservatives were due to be represented by Michael Naughton, who later said that he would be stepping back from the contest due to an “unforeseen family medical emergency”.

Labour - Keir Mather

The 26-year old Oxford graduate was selected by Labour members last night.

He currently works for the Confederation of British Industry (CBI) as a public affairs adviser, and was previously a researcher for Wes Streeting, the now-shadow health secretary.

“It is an honour to have been selected to fight to represent this brilliant constituency. Whilst the Conservatives are too distracted by their own chaos to deliver, the people of Selby and Ainsty have been left without a voice.”

The Yorkshire Party - Mike Jordan

Today the Yorkshire Party Announced that their candidate for the by-election will be a former Tory councillor who quit Rishi Sunak’s party in protest last week.

Mike Jordan represented the Yorkshire Party in the 2019 race for the seat, where he finished fourth behind the Lib Dems with 1,900 votes.

Cllr Jordan said: “Nothing is achievable without real local powers. Yorkshire needs a Regional Parliament, controlling a fair budget.

“Vote for it and make London listen. When the Yorkshire Party wins, Yorkshire wins.”

The Green Party - Arnold Warneken

Arnold Warneken is a North Yorkshire councillor for Ouseburn in the north of the constituency.

“I am an experienced hands-on politician. I have a proven track record and I work tirelessly for the people I represent.”

He finished fifth, narrowly behind Mike Jordan in 2019 with 1,823 votes.

The Liberal Democrats - Matt Walker

The Lib Dems candidate is Matt Walker, who was brought up in Knaresborough and represents the area for North Yorkshire Council.

Reform UK - David Kent

The pro-Brexit party have selected their candidate, David Kent, to represent them in the by-election.

Independent - Andrew Gray

The Harrogate-based sollicitor has used AI to build his manifesto by canvassing local voters on what their priorities are.

Independent - Nick Palmer

Mr Palmer says that Selby needs a break from the “same old Westminster politics” and vote for change.

Heritage Party - Guy Phoenix

Mr Phoenix says that if voters want real change then they must discard the old Westminster parties.

Monster Raving Loony Party - Sir Archibald Stanton

Sir Archibald told the BBC that he would ban greyhound racing to stop Selby and Ainsty “going to the dogs”.

Social Democratic Party - John Waterston

Mr Waterson said that a big priority for him would be tackling anti-social behaviour and public nuisance.

Climate Party - Luke Wellock

Mr Wellock told the BBC that tackling climate change and creating prosperity will be at the top of his political agenda.

Independent - Tyler Wilson-Kerr

Mr Wilson-Kerr said that he would establish a cost of living fund for local residents.

When is the Selby and Ainsty by-election and who are the candidates?