02/09/2016 08:42 BST | Updated 01/09/2017 06:12 BST

Starting To Think About How A Progressive Alliance Could Actually Work

It is clear that Labour alone are not going to win an absolute majority in Westminster in 2020.

That is probably the deepest reason why there is more and more talk about the possibility of some kind of 'progressive alliance', to deliver real democracy and to pose an alternative to endless, un-green right-wing rule in the UK.

So, how do we get there? Plenty of us believe that progressive parties need to start to discuss - to at least consider the possibility of - some kind of electoral pact. A 'popular front' to avoid fragmenting the vote among ourselves in winnable seats looking towards electing a Parliament in 2020 that would have a progressive majority for democratic change. For mending our broken democracy.

But how do we move from talk to action? Well, we need to have some kind of plan. Think tank Green House, which I chair, has gone beyond op-ed articles toying with the principle of progressive pacting to produce a multi-authored report looking into how a 'progressive pact' could work, and examining its pros and cons.

The report will be formally launched next week at the Green Party Autumn Conference in Birmingham, at a unique panel to discuss progressive alliances. On the panel will be not only Caroline Lucas, Green MP, and myself (along with Zoe Williams of the Guardian chairing), but also Neal Lawson of Compass, Labour MP Lisa Nandy, and Chris Bowers of the Lib Dems. The possibility of a progressive alliance will be present, in outline.

To be successful such a pact needs to have a real possibility of gains for all parties involved. Political pluralism in this country is not going away and it is ludicrous for Labour to think they can win on their own. For a victory Greens, the Lib Dems, the Scottish National Party and Plaid Cymru will have to be involved too.

There are historical precedents for a progressive alliance. The most striking is the 1903 pact with the Liberals that in effect enabled Labour to get into Parliament in numbers in 1906. Eventually, Labour took over from the Liberals as one of Britain's main parties.

But this time we are not talking about changing the political system from one duopoly (Liberal-Conservative) to another (Labour-Conservative). We are talking about a genuinely pluralist opening up of politics.

Support from all the signatory-parties for proportional representation must be a sine qua non of any progressive pact. After proportional representation has been achieved politicians and the public can re-align far more easily, without anyone having to fear being wiped out.

A more recent precedent for the proposed progressive pact is the little-known 'non-aggression pact' between Labour and Lib Dems which in 1997 was responsible for the destruction of the Conservatives at their hands.

A progressive pact will enable more people to vote for what they believe in and to get it. In 2015 many millions of voters did not vote for what they believed in because of first past the post and the way it encouraged tactical voting. We should seek to trade (or 'vote-swap') Green votes in some marginal seats for enabling Green votes en-masse in seats where, under the pact, we will be able to win. (And the same goes for Labour, and for the LibDems, and for Plaid Cymru.)

In 2020, a progressive pact would enable people to vote for an end to our broken system. It will be a chance for citizens to really take back control.

But we have to get started now. The obstacles are manifold, from inertia to tribalism. But it is time to take the bold step, together, and consider a pact for the common good. The prize is democracy itself - not to mention getting rid of the Tories' unguents Government.

Any leader or leadership-contender in any progressive party unwilling to contemplate such a pact risks leading their party only into the dustbin of history.