The environment is no longer a main issue for Green voters. That shift explains the Green Party’s recent rise. But it’s also a trap.

The party is appealing to a different electorate than its traditional base. Research by the Good Growth Foundation (GGF) shows that the Green Party now attracts a wholly new set of voters, of which only one in five place climate or the environment in their top three issues. Instead, they prioritise the economy, the NHS and tackling poverty.

For most of its existence, the party’s entire political identity was about climate change, the environment and sustainability. That identity is being reshaped. Zack Polanski talks far less about carbon targets or environmental regulation, and far more about the cost of living, broken public services and a political system rigged in favour of elites. The Green leader has been explicit about this shift, openly describing himself as a populist. It is a deliberate rebrand aping sister parties in Europe and, electorally, it is working.

Even without winning large numbers of parliamentary seats, the Green threat to Labour is clear. If Reform wins the by-election in Gorton and Denton next month, it will be in part because the Greens managed to pry away enough dissenting Labour voters.

However, there’s a catch. Green voters have changed faster than the party itself, and they may be in for a shock if the party ends up exercising real power after the local elections in May.

Nationally, the Greens are relentlessly talking about an economy that no longer works for ordinary people. As a diagnosis, it resonates. Polanski has found a language many voters recognise. Polling consistently suggests the Greens are snapping at Labour’s heels, and Polanski is openly talking about lifting his parliamentary ambitions to 40 seats.

But, locally, the Greens’ record has been shaped by something else entirely. In Green councils, a long-standing strain of “small-c” conservative environmentalism can still be found. Sceptical of development, wary of infrastructure, this form of politics is instinctively protective rather than transformative. In many of the places where Greens have performed best (think high home ownership with a deep unease about disruption), their “radicalism” has meant preservation, not change.

New voters are arriving at the Greens because living standards are being squeezed. They are drawn in by the party’s fluency about fairness in a rigged economy. But if the Greens win big in May, the rhetoric they have established could collide with their councils’ nimby-ish actions. Housing sits just behind energy as the living cost Green voters most want the government to tackle. Yet resistance to new homes, including social and affordable housing, remains a recurring feature of Green local politics. Their voters might not appreciate councillors opposing the very developments needed to ease pressure on rents, housing supply and bills.

The contradiction will only become more visible as the party seeks to consolidate the left. Attempting to emulate Plaid Cymru, which now leads the Senedd race having established itself as a credible anti-Reform option in Wales, the Greens will continue down this populist path. But tensions are visible in the parliamentary party. Green MPs range from rural conservationists to urban, activist left-wingers. That ideological diversity was manageable while the party’s footprint was small. As it scales up, it will become a problem. Who decides when environmental protection collides with housing needs? What happens when local opposition undermines national promises on affordability and living standards?

This is the real test the Greens face. Their voter coalition is being held together by a shared sense that the economy is broken. But coalitions survive on outcomes, not diagnosis alone. And until the party reconciles its national rhetoric with its local instincts, its greatest vulnerability will not come from Labour or the right. It will come from the gap between what their voters want most, and what Green politicians are willing to do to deliver it.

[Further reading: The Greens’ defence problem]