Jeremy Corbyn has shifted British society to the left in many ways. He has encouraged a revival of a number of supposedly antiquated notions: the large-scale nationalisation, the strike and the protest. But perhaps most surprising of all is that Corbyn (or more specifically the campaign against him) has brought the name Leon Trotsky into the mainstream of political debate in Britain.

Trotsky hit the headlines when deputy Labour leader Tom Watson claimed that “Trotsky entryists”, who were “twisting young arms”, were responsible for the surging support for Corbyn. Watson even began to peddle a “dossier” of evidence that Labour’s new members and the massive pro-Corbyn demonstrations around Britain were merely the evidence of “Trots that have come back to the party”.

After that, the British press – always open minded about new ways to attack Corbyn – ran with the notion rather freely. The BBC published a helpful primer, “What Is A Trotskyist?”, and the leaders of the British Trotskyist movement have been invited to explain themselves in public, obviously in the hope that their uncontrolled revolutionary rhetoric will incriminate Corbyn by association (it turns out they are often quite mild mannered).

The Trotsky-Corbyn obsession goes back some time. Even during Corbyn’s first leadership campaign last year, the Labour apparatus tried to rig the election by excluding new members from taking part; they called this little project “Operation Ice-pick”, after the weapon used by a Stalinist assassin to murder Trotsky in 1940.

In early 2016, political journalist Michael Crick reissued his witch-hunting book Militant, an account of how the last sizeable Trotskyist grouping within Labour was broken up and driven from the party. Tom Watson described the book as a “must-read for Labour activists”.

In a sense, this is just the latest in the long line of increasingly deranged slanders against Corbyn: that he is an anti-Semite; that he is an ISIS sympathiser; that he is too reluctant to destroy humanity in a global nuclear holocaust; that he pretended to sit on the floor of a train.

Each accusation has had a few weeks to run in the press. But the accusations about Trotskyism are different: the accusers seem really to believe them. They publish and circulate Watson’s “dossier” and Crick’s anti-Militant “war manual” with an air of panic that suggests they really have something to fear from the “Trots”. What is it?

Trotsky has always been equally terrifying and impressive to establishment politicians. Winston Churchill wrote that he combined “the organising command of a Carnot, the cold detached intelligence of a Machiavelli, the mob oratory of a Cleon, the ferocity of Jack the Ripper, the toughness of Titus Oates”.

An American Red Cross officer performing diplomatic work in post-revolutionary Russia observed that Trotsky was “a four-kind son-of-a-bitch, but he’s the greatest Jew since Jesus Christ”.

But to the Russian working class, and to the workers in the revolutionary movement that surged across Europe in the years following World War One, Trotsky was the “organiser of victory”.

After years in exile, Trotsky had returned to Russia in 1917 when the revolution was in full flight. Throughout 1917 he argued, with all the power of one of the great orators of modern politics, that the working class should seize power themselves. In October, he helped organise the most open and democratic uprising in history.

No wonder that he figures in the nightmares of modern-day Labour Party bureaucrats, whose immediate political survival depends on “Operation Ice-pick”, and to whom the active involvement of working class people in politics is a threat, not a goal.

Trotsky’s capacity to frighten the privileged and inspire the oppressed reached its zenith in the years following 1917. As the founding organiser and leader of the Red Army, he led the successful military defence of the Russian revolution against the shocking brutality of the capitalist counterattack.

Fourteen armies invaded Russia, attempting to exterminate the revolutionary workers’ movement; Trotsky’s Red Army defeated them all. And in the period that followed, as a major figure in the international revolutionary movement, Trotsky worked to encourage workers across national borders to work together to overthrow their exploiters.

It was in this time that Trotsky was subject to the most grotesque anti-Semitic, anti-Communist, anti-worker slanders, portraying him as a Jewish subversive who had conjured up a wild mob of illiterates to slaughter civilised people and conquer the world.

This slander is now wielded against Corbyn, who is accused by the press and his enemies in Labour of sympathy for Trotsky, the alleged perpetrator of “mass slaughter”. But mass slaughter is not a problem for the ruling class: only a couple of weeks ago, they were criticising Corbyn for his refusal to endorse the use of nuclear weapons. And he has all along been attacked for his hostility to imperialist bloodletting in the Middle East.

The ruling class around the world breathed a sigh of relief when the Russian Revolution was strangled by Stalin and its emancipatory essence replaced by authoritarian dictatorship. Trotsky was exiled, and then murdered by Stalin’s agents. It is telling that Corbyn’s enemies in the Labour Party jokingly identify with this crime when they engage in anti-left purges.

This time of exile and its aftermath was also the time of “Trotskyism”: when first Trotsky, and then his successors – facing brutal repression from Stalinists, fascists and “democrats” – worked tirelessly to maintain a political current that was both revolutionary Marxist and anti-Stalinist.

It was a period of heroic endurance in the most difficult circumstances, as Trotsky’s supporters were driven to the fringes of the workers’ movement. For many decades, it seemed that the only possible paths for working class politics were authoritarian Stalinism or an ever more tepid reformism. The leaders of these currents convinced themselves that the threat of a radical working class was finished and that “Trotskyism” was a bad joke.

That joke’s not funny anymore. Certainly, Tom Watson’s paranoia is absurd. Eighty years ago, Stalin accused Trotskyists of collaborating with Nazis to blow up Russian mines and railroads; now, Corbyn’s challenger, Owen Smith, accuses “entryists” of organising people to laugh at him during leadership debates. Trotsky’s poltergeist is not throwing the young Corbynistas into motion; Trotskyist political groups are not directing the political awakening of hundreds of thousands of leftists in Britain galvanised by Corbyn.

But the wager of Trotskyism is paying off. History did not end with Stalin’s coming to power, or with Thatcher, or with Blair. Hundreds of thousands – perhaps millions – of young people, organised workers and socialists can come to defy the orders of respectable Labour politicians.

Mass demonstrations, new political organisations and old questions about socialism and capitalism can once again appear within the workers’ movement. Those who make a living from running the current political system are right to fear this process. Things are just starting out now, but Trotsky’s life and ideas indicate where it can end – in workers casting off their shackles and taking command of their fate.