If we have learnt anything from Brexit, it’s that we need to be prepared.

Leaders of UK Green Parties have called for progressive parties to work together to beat the Tories at the next election to then call for a second general election under fairer proportional representation. That means Greens will have to work with Labour, Lib Dems, and Plaid Cymru to secure a majority in parliament, taking control of marginal seats.

This sounds well intentioned, but with a snap general election to potentially occur as early as November, we need to have a plan of action in place for every circumstance. To many, the call for working with Labour and Lib Dems, antagonists of Greens for many years, is not an appealing prospect. Especially considering that there is no democratic mandate set forward by members, there has been some discontent among the Greens as to whether a progressive alliance will compromise our principles and whether the leaders were correct in announcing these plans before they were universally agreed.

Nevertheless, if this is going to happen, we need to get organised now. We need to be thinking about the best way this can work, and what happens if it doesn’t. We need to consider the opinions of local Green Parties and ensure that this is not top-down decision making. And most of all, we need to question whether the likes of the Liberal Democrats and the Labour Party will work with the Greens.

Firstly, we need to consider the practicalities of a progressive alliance. What will it look like and will people vote for it? One approach could be the agreement for parties to stand down candidates in certain areas. For example, Greens may consider not fielding a candidate in Brighton Kemptown, which was a slim Tory-Labour marginal in the 2015 elections. But it might not all be sacrifices for the Greens. In the Isle of Wight, if Lib Dems and Labour were to stand down their parliamentary candidates, Greens would be neck and neck to gain a Conservative seat.

This method may cause frustration among local parties though – whichever the affiliation. Few parties will welcome an opportunity to stand down in lieu of a victory elsewhere in the country. So as a second option, rather than necessarily standing down candidates, the parties could field a candidate under a unified collective party, such as the Labour-Green-Lib Dem Coalition, or even as simple as The Progressive Alliance. This would work similarly to the Labour and Co-Operative Party candidates, but on a much more temporary basis. Parties would work together to choose the candidate, bearing in mind the electorate of the area, and synergistically work together to get out the vote.

There is the problem of who decides which constituencies will be subject to this strategy. There will have to be a centralised, elected committee ready to make these decisions, but they will also have to respect the autonomy of local Parties, whether they are Labour, Lib Dems, or Plaid Cymru. Consultation and organisation will be the key to create a functioning and effective pact. Every group must enter this plan open-minded and ready to compromise, and that includes ensuring the leadership does not dictate these plans hierarchically.

A successful electoral pact will result in a temporary coalition, but we have to be prepared for defeat too. The EU referendum showed our complacency over the result. We panicked, and we put all our resources in campaigning with little thought over what we would actually do if more voters wanted to leave than remain. What would happen if the same occurred from a general election where the anti-Tory parties agreed a pact? It is a dark thought, but the prospect of a UKIP-Tory coalition would bring the UK into a new age of senseless supercharged austerity, and we need to be prepared.

However, the electorate appreciates balance and looks kindly on seeing politicians work together. In which case, the potential risks of a progressive alliance pale in comparison to the obvious benefits. Passing proportional representation and securing an elected upper house will bring us up to date with global democracy, which the Conservatives are currently ignoring to maintain their illegitimate power. But afterwards, what do we want to do with this alliance, and how soon should a general election be called?

This is just a starting point for thinking about allying ourselves with parties we have been fighting for decades. It could lead to a new era of co-operation in politics. It’s time for us to talk about this together as a party and put forward a plan that Labour, the Liberal Democrats, and Plaid Cymru cannot refuse.