Jeremy Corbyn could not get ‘wasted on the Kool-Aid’ even he tried, whatever the protestations to the contrary from one opponent last week. Soft drinks by definition contain no alcohol. The whole purpose of them is to ensure that consumers stay sober.

Ayesha Hazarika’s allusion was of course to the infamous Jonestown Massacre of 1978, which saw an American cult guru convince 900 followers living in a commune in Guyana to swallow the said brand of soft drink, cut with cyanide. The event marked the biggest mass suicide in modern history.

See what she did there? The man who secured over a quarter of a million votes from Labour Party members supporters and trade unionists as recently as last September is seamlessly elided into a deranged sect leader, ordering small numbers of isolated followers to top themselves in the fastnesses of a Latin American jungle.

Yet Ms Hazarikia’s offering is the only the latest variation of this utterly daft trope. Google indicates that Corbynism has been described as ‘a cult’ or ‘cultist’ by heavyweight publications ranging from the Guardian, Telegraph, Evening Standard, New Statesman, Spectator, Scotsman, and numerous others.

If you are going to make charges like that, you need to stack them up. Resort to offensive analogies that might just about pass muster at a north London middle-class stand-up comedy gig are not a substitute for serious debate on matters as weighty as the future direction of the Labour Party.

Never mind that under Corbyn, Labour has increased its vote share on its 2015 general election showing, and grown its percentage majorities in all four by-elections fought under his leadership. Never mind the reality that if forced to defend his position over the summer, he will start any contest as favourite, and likely win. Just write him off as the reincarnation of Jim Jones. Job done.

What, if anything, justifies such extraordinary invective, far in excess of that applied to any other mainstream party leader in recent decades? Can it be seriously contended, for example, that Corbyn is now an object of religious veneration? Well, I haven’t noticed too many Churches of the Blessed St Jezza opening up lately, so I guess the answer is no.

Of course he inspires enthusiastic support. But after several decades in which many observers have complained of public disengagement with politics, this is actually a good thing. Let’s value it, not deride it.

If the Momentum logo appears on a lot of T-shirts, that’s promotion, not personal vanity. Nobody accused Hazel Blears of attempting to foster a cult of personality with her ‘nuts about Hazel’ hoodies back in 2007, so why aim the jibe at Jezza?

Nor are the political ideas Corbyn propagates in any way outlandish, surely another requirement of cultdom. Marxist-influenced democratic socialism has been indigenous to the Labour Party since its inception. The Social Democratic Federation was a founding participant, and the tradition has since passed through the Independent Labour Party, the British Socialist Party, Cripps, Laski, Bevan and Benn, right through to current iterations such as Labour Briefing and the Labour Representation Committee.

These ideas have not had much of an airing since the advent of New Labour, but are hardly outwith our intellectual tradition. The Corbynite Labour left is simply the latest inheritor of past projects ‘to bring about a fundamental and irreversible shift in the balance of power and wealth in favour of working people and their families’, to use a formulation from Labour’s programme in 1973.

That ambition now needs to be articulated in terms that make sense in 2016. But in an age in which mass social democratic parties across Europe, from Greece through to France and Germany, have collapsed at the ballot box, it is Labour’s only realistic option.

The downside risk lies in not moving radically beyond the policies that have lost Labour the last two elections. If we remain limited by constraints put in place more than 20 years ago, the 2015 result in Scotland could easily be replicated across England and Wales, and that in a matter of months.

Also of note is Ayesha’s inversion of the ‘political food chain’, to use her own all-too-revealing terminology. Labour activists are decidedly not tasty snackettes for the delectation of their parliamentarians. Labour MPs are in Westminster as representatives of constituency Labour parties. If they forfeit the confidence of local activists, they should lose their imprimatur. That’s called democracy.

MPs frequently counter that their mandate derives not from party members but from the electorate, for whom they claim to speak. OK, let them run as independents against an officially endorsed Labour candidate, and see how far they get.

The final aspect of the Corbyn cult myth is the implicit suggestion that the Labour left are mindless underlings. You only need to attend some of the closed meetings and subscribe to some of the internal email lists to know that true friends will always give it to you straight.

Nobody seriously maintains that the man is a polished media performer. Nor has the current Labour leadership developed an easily encapsulated handful of signature policies that can be sold on the doorstep, a matter to which it should have attended months ago.

Our backing is not a blank cheque. Were there an alternative leader in waiting in the wings, possessed of the charisma and intellectual substance to devise a prospectus that would guarantee a victory at whatever date the next general election is thrust upon us, that person would deserve consideration on her or his merits. But there is no sign of any such superhero yet emerging from the PLP.

Unless and until that happens, the full weight of Labour’s left factions - which include not just Momentum, but the Labour Representation Committee, the Campaign for Labour Party Democracy and Labour Briefing - is behind Corbyn. And Jeremy isn’t going anywhere soon.