THERESA May and her shambolic Conservative government have made it through to the long – unnecessarily long – summer recess by the skin of their rotten teeth. But only because four renegade Labour MPs shamelessly bailed them out on a decisive vote. Otherwise we’d be in the throes of a second General Election in a year. Only this time the polls are suggesting Jeremy Corbyn would be the victor, albeit due to Tory votes haemorrhaging to Ukip. So thanks to the Maverick Four – Frank Field, Kate Hoey, John Mann and Graham Stringer – Theresa May continues in office, though definitely not in control.

Prior to the Maverick Four lending their votes to the Tories, it looked like Corbyn had managed to dampen down threats of a reselection war within his party. The right has mostly settled into a grudging acceptance that Corbyn is here to stay while the party leadership – sensing Number 10 within sight – wants no distractions. While there has been much talk about introducing mandatory reselection of sitting MPs – which would inevitably lead to many right-wingers being ditched – Corbyn has shied away from confrontation.

But the Maverick Four have changed all that overnight. Labour’s rank and file are out for blood. After all, why chap doors in the rain only to elect folk who cavort with Nigel Farage or who vote in the Conservative lobby when the chips are down.

Until now, Labour’s candidate selection process has been largely peaceable – or at least as peaceable as these contests ever are. True, where sitting members are retiring, Momentum has been getting more left-wing candidates selected. But the right is far from dormant. In Scotland, for instance, Pam Duncan-Glancy has been reselected as Labour’s parliamentary candidate for the marginal seat of Glasgow North. She beat the Unite and Momentum-backed nominee Agnes Tolmie by a substantial 63 votes to 29. Pragmatism has been triumphing over ideology, at least for candidates with a record of hard work and demonstrable local popularity. But now we are in a political firefight.

The first likely candidate for the chop is Kate Hoey, whose local Labour Party has just passed a unanimous vote of no confidence in their MP of 27 years. No-one could call Kate Hoey a typical Labour backbench robot. An Ulsterwoman, she started out on the far left as a youthful member of the Trotskyist International Marxist Group – as indeed was I. But Hoey’s early leftism reveals more about her eccentric approach to politics than anything else. If she has a personal philosophy it has more to do with libertarianism than communitarian socialism. Hence her opposition to banning fox-hunting and smoking in clubs. But in practice, her version of libertarianism smacks more of Ulster petty bourgeois bloody-mindedness than any radical vision of human freedom from bureaucracy. Hence her support for selective grammar schools, immigration controls and, indeed, Brexit in a constituency that voted 78% Remain.

You might ask how Kate Hoey won the nomination for the safe Labour seat of Vauxhall in London in 1989, succeeding Stuart Holland, the original brains behind Tony Benn. The answer is: she didn’t. The Vauxhall constituency Labour Party voted for Martha Osamor, a black, Nigerian-born activist. But this decision was set aside by Neil Kinnock and the Labour national executive committee who imposed Hoey on the local membership – something to remember whenever our Kate talks about democracy.

So why is Kate Hoey risking her safe Vauxhall seat? The British establishment has a proven way of dealing with dissidents – by incorporating them into itself. Ramsay MacDonald, Labour’s first prime minister, started off as a fire-breathing, left-wing Scottish home ruler and ended up leading a national government with the Tories.

I’m very sure that Kate Hoey (who was an unpaid adviser to Boris Johnson when he was London mayor) and likewise Frank Field would succumb to the chance to “serve the nation” in a future pro-Brexit national government led by Theresa May. Even if that never happens, expect the Tories to give Kate and Frank an ermine robe each.

However, Labour’s internal crisis is more complex that a simple showdown between right and left. The huge increase in Labour Party UK membership – to 552,000 compared with a derisory 124,000 (as of March) for the Tories and 118,000 for the SNP – has fuelled a demand for positions to be filled by one-member, one vote (OMOV). This would generally favour left-wing candidates supported by the pro-Corbyn Momentum tendency – Corbyn himself is only leader because of OMOV. However, big, affiliated unions such as Unite are determined to keep a system of internal voting that gives them a direct say.

There have been conflicts between Momentum-backed candidates and Unite nominees, even where both have the same left-wing views. Most spectacularly, last March Jon Lansman, Momentum’s founder, was forced to abandon his bid to become Labour general secretary, in favour of Unite’s candidate, Jennie Formby. In fact, the dominant role of Unite (the UK’s biggest union) inside Labour is producing its own tensions. Unite is Labour’s biggest single donor and supplies half-a-dozen current or former officials working in key party posts. Aside from Formby, these include Karie Murphy, who runs Corbyn’s private office, and Jim Kennedy, who chairs the key committee that approves candidates.

The historic experience has been that the union leaderships – when the political chips are down – act as a break on the leftward inclinations of Labour governments. If a Corbyn administration is facing a flight of capital and a trade war with America, how will the traditionally conservative trade union leaderships react? Len McCluskey, boss of Unite, was not an initial supporter of Jeremy Corbyn, though he backs him now. McCluskey is thought to favour Emily Thornberry, Labour’s shadow foreign secretary, as an eventual replacement. While union affiliations anchor Labour to the working class, giving the union bosses too much power in the party has always blunted Labour’s radicalism.

How will Labour’s travails play out in Scotland where the Blairite right-wing is still powerful despite the election of Richard Leonard, a Corbyn ally? Leonard has kept the peace internally by continuing to rain fire on the SNP government, thus letting Ruth Davidson’s Tories off the hook. But this disastrous policy – under Kezia Dugdale – handed the Conservatives an easy second place in last year’s General Election. Under Mr Leonard, Labour still trail third in Scotland behind the Tories. After the betrayal of the Maverick Four it looks very much as if Leonard could even lose seats back to the SNP. In which case, expect Anas Sarwar and the anti-Corbyn right to make a comeback.

If Labour’s radical left in England is ever to succeed, it has to think outside its historical comfort zone. Labour do not run candidates in Northern Ireland, so why do so in Scotland? By not splitting the progressive vote, Scotland’s natural left-wing majority would eliminate the Tories north of the Border.

English Labour organised as a mass political movement, with OMOV elections internally and purged of its Blairite canker, could see off any Tory or centre party. Then together we can build a progressive future in these windy Atlantic islands.