The loss of the only Green seat in Parliament would be a “catastrophe”, a progressive campaign group has said.

Politicians and activists from across the political spectrum have reacted to Tom Gray’s selection as Labour’s candidate for Brighton Pavilion.

The music industry activist defeated comedian Eddie Izzard and local councillors Birgit Miller and Lucy Helliwell in a hustings yesterday.

However, political group Compass, which calls for electoral reform, said that the Greens' loss of representation in Parliament would be a disaster for hundreds of thousands of Green voters nationwide.

James Joughin, spokesman for the Brighton and Hove branch of the group, said: “Labour’s selection of Tom Gray to be the party’s candidate for Brighton Pavilion represents a serious challenge to the Green Party’s only Westminster seat and signals we are likely to see a ramping up of progressive in-fighting across the constituency ahead of the next general election.

“If the Greens were to lose any representation at the national level, it would be a catastrophe - both for pluralistic progressive politics generally and for the hundreds of thousands of Green Party voters whom our electoral system has deprived of a voice.”

Former Green Party leader Sian Berry will face off against Mr Gray as she fights to keep Brighton Pavilion in Green hands at the next election.

She told The Argus: “For us, the work to keep a clear and powerful Green voice in Parliament has been going strong for months and will continue now we can put a face to Labour’s campaign.

“Every day I go out and knock on doors, people are telling me they are proud to have voted Green for over a decade and they are desperate to see a change in government.

“They still want to be represented by someone who will stand up for them and not have to follow the party line.

“We know from the polls that there will probably be hundreds of Labour backbenchers in Westminster after the next general election who will be told how to vote by their leader.

“For 13 years, Brighton has voted for something better than that, and they say they will vote for me because they trust me to carry on Caroline Lucas’s excellent record reflecting Brighton’s unique voice in Parliament.”

Caroline Lucas, who has been the MP for Brighton Pavilion since 2010, is not standing for re-election when voters go to the polls some time next year.

Ms Lucas said: “Having spent the last 13 years talking to residents in Brighton, I know that they desperately want to get rid of this cruel and heartless Tory government.

“Sian has the experience, dedication and conviction to make sure that Brighton Pavilion gets heard in Parliament.

“There is no possibility of a Conservative winning in this seat and we don’t need another Labour MP in Brighton who is told what to do by their increasingly disappointing leader - we need someone who will stand up for our community, make sure nature has a voice and hold the next government to account.

“She has the skills and the support to get this done.”

The Argus: Tom Gray addressed Labour members after being selected as the party's candidateTom Gray addressed Labour members after being selected as the party's candidate (Image: Tim Rowkins)

Tom Gray said he was “delighted and humbled” to be selected as Labour’s candidate, with the party’s MPs, activists and artists describing him as a “dedicated, intelligent [and] compassionate candidate”.

Alastair Campbell, former Downing Street director of communications under Tony Blair, was among them and said: “Good to have music industry representation - all part of the cultural superpower plan Labour should put centre stage.”

Brighton and Hove’s two Labour MPs, Peter Kyle and Lloyd Russell-Moyle, also congratulated Mr Gray.

Mr Russell-Moyle, MP for Brighton Kemptown, said: “Having a strong voice for night time industry and live music is so important in Pavilion and Parliament - hope [Tom] will be joining me on those green [Parliament] benches soon.”

Peter Kyle, MP for Hove, said that Tom would be an “outstanding Labour MP for Brighton Pavilion”.

He said: “Tom has always been an unstinting champion for rights and fairness.

“In Pavilion, only a vote for Tom can deliver a Labour government, and I can’t wait to support his campaign.”

Labour is hopeful of winning in Brighton Pavilion at the next general election following a landslide result at the local election in May.

However, some Green activists signalled their confidence in keeping their seat in Parliament following Mr Gray’s selection.

Nate Higgins, the Green Party’s democracy and citizenship spokesman, posted: “Sian Berry is going to make an exceptional MP.”