The question of a Progressive Alliance is now on the political agenda. Calls for an anti-tory alliance are heard from figures as diverse as Corbynite MP Clive Lewis, Corbyn aligned journalist Paul Mason and elements in the SNP, Plaid and notably the Greens. Compass supports saying “thousands now back it” (September 27 th briefing). But the idea needs millions to back it to work, and it is undeveloped.

It is also run counter to the dominant theory in the Labour Party that the Party is on course to win the next election. The leadership contest carried the strapline that it was about “the next Prime Minister” and this was echoed at the Labour conference this year. While some Labour polls show a majority of members would back a PA, the conference was all about what Labour would do in government. Yet the long term electoral decline of the party means a parliamentary majority is a pipe dream.

Labour has suffered electorally outside its traditional heartlands like London. Scotland is lost for the next election at least and UKIP is making inroads despite losing Farage, as the EU referendum showed, particularly so in the North East. Even before the boundary review, Labour’s chances were slim.

The chances of a majority are not only growing slimmer as the polls turn against Labour and favour Theresa May, but also give May the opportunity to reduce Labour to a rump. The chances of an early election seemed slim because of the Fixed Term Parliament Act, but with Labour doing badly and UKIP in disarray pressure on May to cut and run is growing. An early election would turn Labour into a rump, yet grasping this seems beyond the Labour membership.

It is well understood outside the party, and the Progressive Alliance is the consequence. If Labour is to govern it must have third party support, and working this up before an election seems logical. Yet it is also fraught with problems, particularly if the Tories use it against Labour. There is no doubt that fear of the SNP holding Labour to ransom was a key reason for Miliband’s failure in the last days of the 2015 campaign.

Arguments against include the difficulties of achieveing any agreements that would not lead to public disputes inside the parties – the Labour Left is already arguing PA would water down pure socialism, though as David Pavett has said, even with Corbyn the Party is unlikely to be pure socialist. The SNP would not stand down in Scottish seats for Labour and the Lib Dems and Greens have few seats where they matter, so a 1903 type electoral pact is unlikely.

The net effect of negotiation could increase the fear of unstable government on the lines of the French Fourth Republic. Electors want to know what they are getting and a single party that can form government is attractive – as was proved in 2015. Paradoxically a move aimed at preventing the Tories winning a majority could lead to the Tories doing just that. If May can hoover up the 3.8 million UKIP votes over Brexit, the mountain that an anti Tory alliance has to climb would get bigger.

A more viable strategy than a formal alliance is to campaign on specific issues where there is anti-Tory agreement. Politicians working together on joint platforms, gets the electorate used to co-operation, reducing fears of a post election coalition. Issues where this could happen are clearly the threat of a one party state – the virtual gerrymandering of the boundary review can be opposed by a nexus of politicians campaigning for pluralism. Organised registration of the young makes a lot of sense, as the individual registration system has been disasterous, leading to a cull of young voters.

The Brexit campaign must unite opposition forces and where Nicola Sturgeon leads on opposition to xenophobia others must follow. However it is not just anti-foreigner feeling that is worrying – the rise in homophobic and racist attacks is part of the turning away from modern society. May is pandering to this to win over UKIP votes. The battle to block her initiatives can unite politicians who want a pluralistic and tolerant diverse society.

A formal Progressive Alliance is less viable than working together across issues. I once argued Britain looked like Weimar, but the BNP was countered. However the xenophobic right morphed into UKIP and took over the Tory Party. May is pandering to it, and the future is very bleak if it is not thrown back – Progressives simply have to work together.