There are three misconceptions about the far left. Not one of them is true. And all of them hide the crisis in the opposition, which is giving a dangerously incompetent Government unparalleled and unwarranted freedom of manoeuvre.

The first is that its obsession with doctrinal disputes makes far leftists Pythonesque figures of ridicule, rather than a malicious force with malign political consequences. We are then told that the young pass through a ‘left wing phase,’ as if it were a rite of passage like drinking cider or puberty. They believe extreme ideas and shout angry slogans, but when they realise the true nature of the far left they grow up and move on. Finally, moderate commentators always reach for the consoling belief that there are realists among the leaders of extremist movements. Unlike their ideological followers, who can afford to spout crackpot ideas and live in the dream world of the cult, a few near the top will confront reality and moderate their views. Just as Douglas Carswell is meant to be the acceptable face of Ukip, and western diplomats were once convinced they could do deals with the ‘moderate Taliban,’ so commentators assume that Jeremy Corbyn and the leaders of the trade union movement are less extreme than the Trotskyist entryists determined to take over the Labour Party.

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Political journalists had the chance to assign traditional roles when Laura Murray, women’s rep for Momentum and an adviser to Corbyn’s shadow cabinet, pushed all the right buttons. The Trotskyist sect, the Alliance for Workers Liberty was trying to wrest control of Momentum from its founder, Jon Lansman, and force it to abandon Corbyn, she warned. Apparently there was, after all, a moderate faction in Momentum, and Murray was its voice. As the papers told it, Murray’s moderates were opposing a delegate-based system for Momentum elections that would allow 'the hard left (to) be able to control Momentum’s future'.

Inevitably, the Python jokes came out to reassure readers that the dispute did not matter – ‘the People’s Front of Judea is alive and well,’ said one reporter. Meanwhile Murray herself gave every indication of being an innocent child who had wandered into leftwing politics full of youthful ideals, only to be shaken by the banal reality of socialist politics. At one point she exclaimed

I never could have imagined the sheer capacity that some people have to endlessly argue with each other, either over the boring bureaucracy of structures and process or pointless motions on policies they can’t implement because they’re not actually a party.

I confess my first reaction was 'bless, she’ll learn'. Then I read her ill-written piece carefully. To understand the collapse of the Labour party just at the moment we needed it most, you must understand the history of the far left. Stalinist communists used to hate and murder Trotskyists. By contrast, at least some Trotskyists could give the impression that they were against mass murder in the name of the revolution. These differences are less pronounced than they once were. But it is a measure of the morally and politically disastrous position Labour is in that these old battles, once of interest only to left-wing historians, have contemporary force.

Corbyn and much of the trade union leadership are the Stalinists’ fellow travellers. Corbyn wrote regularly for the communist daily the Morning Star, and still praises it today. His chief spin doctor Seumas Milne regrets the fall of the Soviet Union. The 'Stop the War' coalition Corbyn chaired has replaced support for the Soviet Union with support for Putin, as indeed has Milne. John Rees, Stop the War’s national officer, says that he is against ‘regime change’ in Syria. For good measure, the ‘anti-imperialist’ backed Russia’s annexation of Crimea, describing it as the 'Russian state defending its interests'.

Most pertinent for our story is Andrew Murray, of the Communist Party of Britain, who was once parliamentary lobby correspondent for the Soviet state-owned Novosti news agency. He is now Len McCluskey’s chief of staff at Unite, and yet another Stop the War apparatchik. As luck would have it, he is also the father of that apparent enemy of the 'hard left' Laura Murray. No less a figure than Jeremy Corbyn hired her as a Labour party adviser.

The Alliance for Workers Liberty is, by contrast, resolutely anti-Stalinist. Its origins lie in Trotskyism. Shachtmanite Trotskyism if you want to be picky about it, named after Max Shactman, a mercurial American activist, who could at least see Stalin’s terror for what it was, and eventually gave up on Marxism. I will say this for the AWL, amid its totalitarian theory and regimented thinking, it has a record of honourable opposition to modern dictatorships, and has not joined the rest of the far left in supporting any secular or clerical variant of fascism as long as it is anti-Western. Naturally, the heirs to the Stalinists of the 20 th

Go through the article by the supposedly innocent Laura Murray and you see the ghouls of the past, shaking off the graveyard soil, and stalking the present. She objects to the ‘extreme Trotskyist politics’ of the AWL, in language that a Stalinist from the 1930s would instantly recognise. The supposed moderate damns them for their ‘uncritical support for Israel’ – by which she means that it does not want to abolish the ‘Zionist entity’ and drive the Jews into exile – and its ‘fanatical support for the European Union’ – by which she means that the AWL doesn’t see the EU as a capitalist club, as any supporter of Corbyn must.

Murray junior’s writing is littered with the robotic denunciations of communism, which again will be familiar to anyone unlucky enough to have wasted their youthful rebellion on the far left. 'The sectarian attitude taken by Trotskyist groups within Momentum is destructive to our movement,’ she cries. Allow them to take over and ‘their Momentum Party will die the same pathetic death as every other Trotskyist party in British history’. You can almost hear a voice grown harsh from jeering.

I have no wish to embarrass the AWL by defending it. Indeed, I am not defending it, I am just pointing out that cliched thinking and an inability to understand the extremisms of right and left that are flourishing around us is stopping us seeing the Labour party for what it is.

The true extremists on the Labour left aren’t naive young idealists but the leader of the Labour party and the official opposition, and the leader of Unite, the biggest union in the country and the most powerful voice in Labour politics. Or to put the same point another way, you understand the scale of the party’s crisis only when you grasp that the Alliance for Workers Liberty, a secretive, ruthlessly disciplined Shachtmanite-Trotskyist-Marxist-Leninist sect, is now the voice of moderate Labour.