All too rarely you get a moment in politics that electrifies you – that makes all the meetings and the struggle worthwhile. One such moment happened to me at the Green Party conference in Harrogate earlier this week. It was, I believe, a profound moment for all of us who want a better world. But before I tell you about it – a little context.

Compass, the organization I chair, helped create the ‘progressive alliance’ – the idea of parties working together for the common good. When Theresa May called a snap election, a long-term cultural transformation strategy quickly and understandably got boiled down to transactional deals – how to stop the Tories getting a landslide. The Green Party, at least nationally, were the only ones to take it seriously and stood aside in a number of key seats to ensure the progressive vote wasn’t split. It worked - in that it helped stop the landslide. If it had worked better it could have put Corbyn in Downing Street. But neither the Lib Dems nor - especially - Labour took the idea seriously at the top.

For the Greens it was bitter sweet. May was thwarted but half their vote from 2015 was lost at people voted tactically. So the progressive alliance was a hot topic of debate at their conference. Should the Greens continue to advocate alliance politics?

This is where the epiphany happened. With Caroline Lucas and Jonathan Bartley, the two co-leaders of the Greens, Compass organized a rather ad hoc session to hear what Greens activists felt about the progressive alliance – good and bad. There was bad – to the extent that one delegate told me (a Labour member) I wasn’t welcome at the conference and neither were my views on what the Greens should do.

But then as we sat in small groups and people explained their experiences of working locally with other parties and this guy just starts saying that the Greens should persist with the progressive alliance simply because it is the right thing to do, that if the Greens aren’t generous and open then no one will be. That if we want a new politics someone, despite the pain, must show the way. Even if Labour doesn’t reciprocate, the Greens have to light the path to something better.

My heart melted at the wisdom and kindness of this sprit, reflected by all those who took part in the conversation – who sat and listened, learned and changed their minds as people spoke.

Green Party members are doing something remarkable. They are giving birth to a new politics. As something so new, this political culture - open, plural and collaborative - is extremely fragile. What happened during the election is just the first and earliest signs of this new politics. It will wobble and be weak for some time. But in a networked, complex and chaotic society that faces huge challenges, it is the only way to do politics in ways that really transform society and save the planet from us.

Some in the Greens remain implacably opposed to the idea of the progressive alliance. Why should they make a sacrifice when no one else will? At one level it’s a pretty understandable reaction. And yet here is a small party behaving in the biggest possible way.

The ripples will flow from this. Already, the Lib Dems are standing aside for the Greens in Richmond in May. In Labour support for proportional representation – the midwife of this new politics - is growing strongly.

But it won’t be easy. Nothing on this scale – the transformation of our political culture away from winner takes all – ever is. Labour because of its history and culture cannot yet embrace this future. But it will have to or it will look increasingly out of date and mean spirited. It cannot talk the language of solidarity and then practice a politics of raw competition – especially with people it largely agrees with.

It causes me the most profound sense of political sadness that Labour cannot yet even say ‘thank you’ to the Greens and Green voters for the sacrifices they made during the election. Many Labour MPs such as Clive Lewis and Rupa Huq did at their victorious counts – but the leadership still finds it too tough. We have to help them into a better space.

The electorate, people, love seeing parties work together – not subsuming their identity but collaborating for the common good – combining, being humble, generous and empathic.

The future of politics will be volatile. As surges wipe out slim majorities, new ideas, movements and even parties will emerge. In all the chaos and complexity it will be those with the values of compassion and who seek to collaborate that will survive and thrive.

During the election I was exhilarated by the sight on the ground of this new plural politics in action when values, beliefs and behaviors trumped old party loyalties. At Conference, despite the setbacks and the hurt, the flame was strong. The future of these progressive alliances could be felt.

The Greens have probably helped stop a hard Brexit and certainly lots of other draconian legislation that would have been passed with a big Tory majority. Some Greens feel they got little out of it. In this they are wrong. Way beyond lost deposits and swings they have created the conditions for a new politics.

Change will come when we stop fearing each other, stop trying to hoard power for ourselves, stop trying to control others and start to trust and cooperate. In a haunting line at the end of the song In the Deep, the singer Bird York whispers the line ‘if you want to be given everything, then give everything up’. Thank you Greens for renewing my faith in politics and people. You will gain everything.