After years of tortuous, tedious, seemingly endless speculation, seven of the Labour right’s most intransigent MPs - now styling themselves as ‘the Independent Group’ - have today (February 18th) finally opted to take their leave from the party.

The cynicism of this morning’s announcement is belied by its timing. Earlier this month, Labour general secretary Jennie Formby indicated that the party’s National Executive Committee was considering ways of accelerating the trigger ballot process with a view to a possible snap election. Lo and behold, we learn today that these MPs (Chuka Umunna, Chris Leslie, Angela Smith, Mike Gapes, Ann Coffey, Gavin Shuker and Luciana Berger), most if not all of whom were faced with a realistic prospect of deselection, have decided to jump ship.

It is important to recognise (as indeed Jeremy Corbyn has) that Luciana Berger has been subjected both to vile anti-Semitic abuse and dogwhistle smears, including some from within the Labour Party. Berger is certainly right to find this intolerable, and so should everyone else. We have acknowledged previously, and do so again, that there is real anti-Semitism “rooted in some of the wider, limiting and reactionary aspects of the beliefs and culture of Corbynism”. Socialists therefore have a moral and ethical duty to be permanently vigilant against anti-Semitism, against which political education must come to serve as a crucial tool.

With regard to the breakaway project as a whole, however, it is safe to conclude that the overriding driving force behind this breach, for the clear majority of this ‘Independent Group’, is not political principle but self-serving spite. Their refusal to trigger by-elections, and suggestions that the group will stand in marginal seats rather than fighting again to retain the confidence of their existing constituencies seem to lend further weight to this.

To say that in taking this leap, the splitters are taking up their rightful places in the annals of infamy of the British labour movement is perhaps giving them too much credit. Their generous media profile - while affording them a prominence they scarcely deserve - can only do so much to mask their generally undistinguished individual and collective track records, doing the photocopying for Gordon Brown notwithstanding.

Let us put this latest rift in some historical perspective. The 1931 split from the Labour Party - one which could quite possibly have destroyed the party altogether - was led by a serving Prime Minister in Ramsay MacDonald, while the Gang of Four boasted a former Home Secretary, Chancellor and president of the European Commission in Roy Jenkins, a former foreign secretary in David Owen and a former shadow Home Secretary in Shirley Williams. The seven MPs leaving Labour today, on the other hand, have five years of junior ministerial experience between them.

Furthermore, the revisionist tradition out of which the Gang of Four emerged did at one time lead a serious intellectual project with real designs on hegemonising the Labour Party for good. Heirs to the New Liberalism of the inter-war years, revisionism understood many of the limitations of orthodox Labourism and sought to rearticulate social-democratic objectives in a way that took account of changed post-war social conditions.

But like Labour’s Blairites today - in some ways their heirs, though far less substantial intellectually - the revisionists were eventually undone by a protracted crisis of capitalism for which they were unable to devise a distinctive and credible remedy. Left high and dry by the breakdown of post-war Keynesianism, the revisionists found their previous assumptions discredited; the Gang of Four’s split in 1981 merely reflected this exhaustion rather than pointing a new way forward.

Not that any of this prevented the media from praising the party to high heaven at the time. The SDP’s honeymoon saw it (in alliance with David Steel’s Liberals) briefly surge ahead of both Labour and Margaret Thatcher’s Conservatives in the opinion polls, before eventually settling down to 25% of the vote at the 1983 general election; the vagaries of first-past-the-post ensured that the SDP-Liberal Alliance won only 23 seats compared to Labour’s 209, though Labour only surpassed the Alliance’s share of the popular vote by 2.2%.

But as Jon Lansman commented with some relish over the weekend, by comparison today’s Blairite rump is comprised of “marginal figures with marginal politics”. Both the personal profile of the Gang of Four and the support for its politics were orders of magnitude greater than anything the ‘Independent Group’ is likely to muster today. The ambition of the latter, or lack thereof, seems an implicit acknowledgement of this: whereas the SDP no doubt did, initially at least, harbour genuine illusions of ‘breaking the mould’, the new breakaway seems to have contented itself with stirring the pot over Brexit and trying to keep a potential left-wing Labour government out of office.

Indeed, the ‘statement of values’ issued by the group this morning is notable primarily for its sheer vapidity. Preferring to focus on nebulous ‘values’ at the expense of concrete ideas - of which it apparently has precious few, judging by Angela Smith’s authentocrat sneering at “left-wing intellectuals” - the ‘Independent Group’ resembles nothing more than the ‘little Caesars of social democracy’ once sharply critiqued by Stuart Hall; unable to comprehend the reasons behind the “collapse and bankruptcy” of the political centre and the polarisation arising from this, the splitters instead appear to have retreated into congratulating themselves on their own seriousness, gentility and refinement.

The astonishingly empty reference in the statement to “our parliamentary democracy in which our elected representatives deliberate, decide and provide leadership, held accountable by their whole electorate” and how this is allegedly “the best system of representing the views of the British people” is in large part a reflection of the most transparent self-interest. It comes in response to extremely limited internal Labour Party reforms aimed at, in a very modest way, improving Britain’s hollowed out parliamentary democracy, but it is also indicative of reaching towards an ideal post-democratic form, where ‘the right to be heard’ and ‘the duty to lead’ is derived from apparent autonomous charisma mediated through a sympathetic press rather than through representing and responding to ideas, programmes or social forces.

Had the Social Democratic Party been more successful than it ultimately was, it seems unlikely that today’s breakaway would have taken so long to occur. While it contributed to keeping Labour out of office during the 1980s (though it certainly cannot be solely credited for this), it effectively ended the frontline political careers of its leaders. This lesson, at least, is something that Umunna and his colleagues must have taken on board. But their career prospects in Labour were clearly over in any case, and so they have now concluded that they have little left to lose.

What does today’s announcement portend for Jeremy Corbyn’s Labour? It is evidently calculated to make it more difficult for Labour to win any forthcoming general election; it may even prompt Theresa May to call one ahead of schedule (though having all but squandered an opinion poll lead of over 20 points in 2017, she is unlikely to do so in a rush). But the departure of this band of incorrigibles from Labour may, if anything, increase the party’s chances of successfully implementing a left-wing programme if and when it arrives in government.

It should be clear that the Labour left remains in a very weak position in the House of Commons; perhaps as few as 15 or 20 MPs solidly identify with the socialist left. The Blairite right, even with the departure of Umunna and company, remains well overrepresented in Parliament, especially given the weakness of its support at the Labour grassroots and the relative thinness of its social base. It is the electoral necessities of first-past-the-post, rather than a shared commitment to political pluralism, that has held these disparate factions together up to now. But this is no basis for any substantial unity.

All of this poses a serious, potentially existential threat to a hypothetical left-wing Labour government and its ability to put its manifesto into practice. The irreconcilables of the Blairite right were never about to start playing nice under a Corbyn-led administration. Quite the opposite, in fact; should such a government succeed in implementing an anti-austerity programme, the left’s control over the party would be more or less guaranteed for the foreseeable future thereafter. The PLP right knows well enough what the stakes are here.

While it is completely understandable that so many should be so desperate to see the Tories catapulted out of office as soon as possible - and Labour’s uncompromising party political broadcast last week reminded us just how devastating the human impact of austerity has been - matters are not quite so simple as this. There was and remains a very real risk that attempting to govern with a thin majority (if any majority at all) and a discordant rump of 30-40 MPs lobbing brickbats at their own leadership at every opportunity would denegerate into a debacle; one which could set the cause of socialism in Britain back many years.

But most of that rump remains present in the PLP, and for all the relief and even jubilation on the Labour left at the exit of Umunna and his colleagues, the transformation of Labour’s parliamentary ranks remains an urgent necessity and will require much work. Any left-led Labour government needs to be backed up in Parliament not just by nominal supporters but by committed socialists, equipped to withstand the inevitable turbulence that any attempt to govern from the left would bring. The Labour left must not allow today’s schism to distract it from this task.

It is also incumbent upon the Labour leadership and members alike that they do not allow themselves to be dragged into continual mudslinging by this breakaway. Instead, they must press ahead in putting forward a positive case for a socialist Labour government, building on the 2017 manifesto and going beyond it to present new, transformational policies that will not just end the social destruction of austerity, but also lay the foundations for a real and permanent shift of wealth and power towards working and oppressed people. The party must take the chance to further develop and clarify its own positions, and communicate them with renewed coherence.

The departure of Umunna, Leslie, Shuker, Smith, Coffey, Gapes and Berger - quite possibly to be followed by others in due course - presents the Labour Party with a potentially historic opportunity: that of resolving a fundamental political ambiguity, and of deciding whether it is to remain a party of moderate social reform or to forge ahead in renewing itself as a party of radical social transformation. Jeremy Corbyn and the Labour left as a whole must grasp this opportunity.