The city of Brighton and Hove on England’s south coast is home to some of the country’s most eco-conscious voters, and next week’s general election there is as much about climate change as Brexit.

“It’s the only issue really .  . . everything else becomes academic,” said Mike Pelton, 60, a Green Party voter talking to his local candidate last week.

“I’ve been shouting about it in pubs for a long time to anyone that would listen,” he added.

The seaside city has long been a bastion for the environmental cause.

Voters have elected Britain’s first and only Green Member of Parliament (MP) in the last three general elections and it has more party councillors than anywhere else in the country.

But as the world climate emergency becomes more apparent and campaigners such as Swedish teen Greta Thunberg gain prominence, voters elsewhere appear increasingly swayed.

The Greens made the second-biggest gains of all parties in local council elections in May. They then won seven seats in European Parliament polls, more than the ruling Conservative Party.

Other parties have responded by offering an array of new policies ahead of next Thursday’s vote, from planting hundreds of millions of trees to setting target dates for decarbonisation.

Their leaders have also tried to burnish their images with campaign stops at electric car factories, wind turbine facilities and eco-home building sites.

Dave Timms, of Friends of the Earth, said the environment was “rightly a major election issue in a way we have never seen before”.

“It’s a crisis and we have to act decisively,” he added. “However, politicians are not responding equally to that demand.”

The government says Britain is a world leader in tackling climate change but according to Greenpeace, it is on track to miss a whole range of targets in the early 2020s.

Channel 4 television hosted the country’s first-ever leaders’ debate on climate change last week but British Conservative Prime Minister Boris Johnson failed to even show up.

Other party leaders have also been criticised for offering up policies too timid for the scale of the problem.

“The climate issue is huge and I don’t feel like it’s high enough up on their agendas,” said one 38-year-old voter in Hove, who declined to give his name.

“No more just talking, we need to take proper action.”

The Greens are hoping to lure in dismayed voters with their well-established brand and eco-centric policies.

Ollie Sykes, the candidate for the Hove constituency, recalled a resident told him recently that he viewed the party as like tech company Apple: geeky and weird 30 years ago.

Now it was mainstream and vital.

“We welcome ‘green’ policies wherever they come from,” Sykes said.

“But I do worry about the extent to which the commitments of other political parties are genuine in this regard.”

Hove, one of the city’s three Westminster seats, is considered safely Labour, so Sykes and his small team of canvassers are trying to boost the party’s overall vote share and credibility.

The strategy appears to be convincing some.

“I’m not a classic Green voter . . . but I’m a proper convert,” said Nicole Mamane, 51, who has lived in Hove for 16 years.

Typically a floating voter, this time Mamane had already supported the party by postal ballot.

“I did it with my heart,” she said of her decision. “I want a broader church in parliament.”

Ex-Labour voter Celia Godsall meanwhile said she had been inspired to canvas for the Greens after encouragement from her eight-year-old granddaughter.

“I just started to get more involved and here I am today knocking on doors,” she said.

Elsewhere, the Greens are fighting to win.

The pro-Europe party has entered into an anti-Brexit alliance with the Liberal Democrats and the Welsh nationalists Plaid Cymru in 59 constituencies across the country.

It is standing aside in 49 to get a clear run at the Conservatives and Labour – the latter refused to enter into the pact – in 10 constituencies.

They include Caroline Lucas’s Brighton Pavilion seat, as well as Bristol West and the Isle of Wight – all places where it fared well in May.

Lucas, a former party leader who has increased her majority at each election since 2010, is expected to retain her seat in this month’s pivotal elections.

But division over Brexit is a complicating factor everywhere.

“There’s more focus on the environment but I still think the Brexit [movement] pushed it out really,” said Sue Shanks, 64, a Green councillor in Brighton.

“When I talk about climate change they say ‘what about the NHS?’,” Sykes added, referring to Britain’s cherished national health system.