The Greens, expelling activists for uniting to oust Jeremy Hunt? So much for progressive politics | Neal Lawson

If the Green party can’t practise a kinder, more thoughtful politics, who can? Last week, Green party activists in Surrey were summarily expelled from the party for doing everything necessary to beat the incumbent Tory, one Jeremy Hunt. Without question, debate or ability to respond, three local members who had worked hard for the party and built cross-party alliances were given a straight five-year expulsion.

Here’s the backstory. Deep in the heart of true-blue Surrey, a small but determined outpost of Compass members brought like-minded people together from Labour, the Liberal Democrats and Greens to knock down tribal walls and help a progressive candidate win. I’m the director of Compass, which pushes alliances in pursuit of a good society, and in Surrey, in the 2017 electio it was almost successful in doing so. They backed a National Health Action party candidate against Hunt, then health secretary, who came much closer to winning than Hunt found comfortable.

Come this election, activists were determined to build on this work, replacing Hunt with the best placed progressive, who was Paul Follows, the Liberal Democrat council leader. His deputy leader, Steve Williams, was to be the Green party candidate, but his local party decided he should stand aside and give Follows a free run.

So much for the new politics. Now came the old. Williams did the decent thing and told the national Green party 24 hours before the deadline of the local decision. But in response, behind the backs of local organisers, Green HQ imposed another candidate, a London-based party staffer. Off the back of the hard work of local, and now expelled, Greens, this paper-thin candidate got more than 1,000 votes . The impact was perfectly counterproductive to our aims: Hunt held his seat by 891 votes.

Then things got worse. Williams and others received their expulsion notices for publicly backing their Lib Dem colleague. At a stroke, Green presence on the council was slashed, and Greens nationally sent the message that local party democracy and cooperation were to be crushed.

It justifies its decision, claiming the national motion to stand in every seat supersedes local decisions. The party had leeway to let local members go ahead with their plan, just as it didn’t have to expel them. It chose to impose and then crack down.

Related: The Green party won four seats when it should have been 40. Surely it’s clear that Britain needs electoral reform | Ellie Chowns

Of course, the Greens deserve sympathy. The electoral system weighs heavily against the party and neither Labour nor the Liberal Democrats will enter any cooperation arrangements. But the response that “if you can’t beat them, join them” by expelling members who put country before party is a miserable dead end. However tough it is, part of the purpose of the Greens is to demonstrate that a politics of cooperation and pluralism is essential to meet the complex challenges of the 21st century. A politics of proportional representation – which the Greens advocate for – demands cross-party cooperation.

The Greens could be accused of being hypocrites. You can’t encourage tactical support in the seats where you benefit and deny it where it serves other anti-Tory progressives. You can’t credibly turn a blind eye to tactical voting , expecting it only to be done in private, and then expel dedicated party activists who stand aside for the greater good in an electoral system that favours established parties. Not least when the party itself was only targeting four seats in the country.

The tectonic plates of British party politics are breaking up all around us. Labour won 63% of the seats but only 34% of the votes in the general election. Its majority is broad but only skin deep, and oh so brittle. Turnout was down to 52% . The only permanent feature of party politics from now on will be incredible churn and volatility, allied with the threat of authoritarianism.

The response of the old politics is to hold on tighter than ever. To control and expel. But activists and voters are way ahead of the tribalists. What activists were trying to achieve in Surrey is necessary if we are to side-step the descent into anti-democracy of the rightwing populism.

Perhaps, after winning four seats, the Greens feel vindicated. Rightly so – but the point of the party is to be different. Crucially, it must know that means always shape ends. The future we want and need won’t be imposed by the ruthless centre of any party, but negotiated and created for, and by, all of us. That flame of a new political hope is just starting to burn – but it will be stomped out if the national party chooses control over cooperation.

• Neal Lawson is director of the cross-party campaign organisation Compass