The Labour left presumptuously claims to represent the British tradition of dissent, but never tolerates dissent against its command and control politics.

At the meeting of Labour’s national executive committee last Tuesday, to take the most recent example, Diane Abbott preferred abandoning a lifetime of support for the EU to accepting a challenge to the party line.

Dissident voices urged Labour to offer a second referendum on any Brexit deal. Abbott had nothing to say on the threat Brexit poses to jobs and Britain’s poorest regions. She did not think about how Labour’s failure to fight the right and far right was losing it millions of votes. For Abbott, calls for a people’s vote were not a way forward for a country in crisis, but “an attempt to drive a wedge between Jeremy and the members”. Paranoia and leader-worship had replaced any concept of the national or party interest. What kind of leader produces such unthinking loyalty from his followers and, more pertinently, what damage does he inflict on the souls of followers prepared to give it?

Jeremy Corbyn is not particularly interesting. Labour officials tell me that the key to understanding him is to grasp his intellectual inferiority complex, which resulted in him turning to political dogmatism as others with his disadvantages turn to Scientology. The socialist dogmas of the 1970s gave his limited mind certainty and freedom from responsibility, and a set of enduring precepts.

‘Diane Abbott preferred abandoning a lifetime of support for the EU to accepting a challenge to the party line.’ Photograph: James McCauley/Rex/Shutterstock

There had always been a strain on the British far left that opposed European co-operation because “capitalist” Europe threatened to rival the Soviet Union, the 20th-century object of their utopian fantasies. Corbyn had a ready-made anti-European policy right there. Starting with the Stalinist purges of Soviet Jews in the early 1950s, and extending to the wider left after the Israeli-Arab war of 1967, the notion that leftwing antisemitism didn’t exist surrounded him. In this milieu, it was natural to ally with the goosestepping Shia fascists of Hezbollah, and wild-eyed creeps who babbled about how the Jews caused 9/11; natural, too, to use the racist sneers of his class and generation to tell British Jews in his audience they did not understand “English irony”. And… well, I could go on, as you surely know. The point worth noting is that when Jews and genuine anti-fascists complained, he and his supporters treated them as if they were false witnesses hiding their real aim of advancing Israeli interests.

The Daily Mail runs columns undermining the existence of anti-black and anti-Muslim racism and dismisses those who complain as special pleaders with a covert agenda to promote sectarian causes. In Labour, the ethnicities are different but the song remains the same. If you still can’t see him clearly, the best way to think of Corbyn is as the Richard Littlejohn of the left, with John McDonnell, Seumas Milne and Len McCluskey as his commissioning editors.

His followers are more interesting. Politicians and intellectuals who go along with the Labour leadership are not leftwing in any coherent sense. I have yet to hear one of them make a socialist case for leaving the EU and argue it against all-comers. (They don’t because there isn’t one.) I have never heard one of them say that “Jeremy” and his friends may have strange ideas about Jews but the prospect of a radical left government overrides all other concerns.

Instead, they have emptied all content from their politics. Those who think that struggles on the left are ideological have insurmountable trouble explaining why Corbyn supporters loathe Stella Creasy and Jess Phillips, who have unimpeachable records as defenders of women’s rights. They hate them because the far left’s disputes are personal, not political. Its supporters are the equivalent of gang members who will knife anyone who does not respect the boss. If their leaders were to drop their anti-Europeanism or engage in a principled examination of antisemitism, they would too.

George Orwell: ‘Remember that dishonesty and cowardice always have to be paid for.’ Photograph: Ullstein Bild/ullstein bild via Getty Images

In this world, the good of the party and the good of the country are as disposable as cheap tissues. Gang loyalty is the only virtue. Labour politicians, journalists and activists are replicating the faults of the leaders who own them. They match the paranoia of Abbott when they explain away demands for a stand against Brexit as a conspiracy to undermine the left, or denounce those who protest against the re-emergence of the antisemitic conspiracy theory of fascism as “plotters” against Corbyn, as that overrated loudmouth Yanis Varoufakis did last week.

The followers have the leader’s certainty but their certainty lies not in the world of ideas, however half-baked, but in the certain knowledge that they must defend the leadership whatever it does. They too are deeply irresponsible: jobs, living standards, public services, the fears of Anglo-Jewry, the fate of Britain’s regions and the future of EU migrants are no concern of theirs.

During the latest spat about antisemitism, Corbyn’s supporters defended his praise for the work of the Edwardian author John Hobson; praise that, inevitably, was not tempered by criticism of Hobson’s anti-Jewish conspiracy theories. George Orwell had antisemitic prejudice too, they cried, and everyone praises him.

They forgot that Orwell spent his life fighting, not always successfully, to overcome his prejudices. Corbyn has never even tried. They forgot, too, that no one should quote Orwell without first checking that Orwell cannot be quoted back at them. As it happens, Orwell’s words used against the apologists for Stalin in the 1940s can be as well deployed against today’s apologists for Vladimir Putin, Nicolás Maduro, Iran, the Islamist far right and the Labour far left.

He had, he said, “a message to English leftwing journalists and intellectuals generally: ‘Do remember that dishonesty and cowardice always have to be paid for. Don’t imagine that for years on end you can make yourself the boot-licking propagandist of the Soviet regime, or any other regime, and then suddenly return to mental decency. Once a whore, always a whore.’ ”

• Nick Cohen is an Observer columnist