At the end of July I devoted this column to the candidature of Jeremy Corbyn for the leadership of the Labour Party . I concluded thus: "Corbyn… has a problem with Jews… This fear - of imagined Jewish power - has haunted the Labour Party from the moment of its foundation. A Corbyn victory would at last bring this apparition into the open, where it desperately needs to be."

How right I was! But what I now ask you to concentrate on is the wider picture - the likely shape of the Corbyn-led Labour movement and its Jewish preoccupations.

"Blairism" - the broad acceptance by Labour of Thatcherite free-market ideology - is dead. Politically, that's what Corbyn's victory means. But the meaning goes much deeper. Thatcherism was philosemitic. Corbynism is not. That does not mean that I believe Corbyn personally to be an antisemite. It's quite possible (I suppose) that he - personally - isn't.

I say this in spite of the fact that he seems to have occupied some distinctly dodgy political platforms over the years . He's been accused of associating with Holocaust denier Paul Eisen. He's exhorted us to make "friends" with the Hizbollah and Hamas terrorist organisations, which are openly antisemitic. Of course there's always room for repentance. Following his victory, Corbyn wasted no time in condemning Eisen's Holocaust position as "wrong and reprehensible", and claimed that as a politician he had to meet people with whose views he did not necessarily agree. Asked about these matters, Corbyn declared: "The idea that I'm some kind of racist or antisemitic person is deeply offensive."

I was inclined to accept this disavowal, until news emerged that, at a Labour Friends of Palestine fringe meeting during last week's party conference, Corbyn had shared a platform with another unsavoury character. Even if this is explained away as just one more unfortunate misunderstanding, there's a world of difference between Corbyn as a confused innocent and Corbynism as an ideology. Corbynism means that "Israel" is an unmentionable word, not to be uttered even if you are a guest at an event hosted by Labour Friends of Israel. More generally, Corbynism signifies the Labour movement's embrace - or re-embrace - of a visceral anti-capitalist mindset. Last month, in celebration of this return, Corbyn gave notice that he would welcome back into the Labour fold militant activists who had been expelled therefrom.

I am calling on him to condemn antisemitic language

Among those is the former MP for Coventry South-East, Dave Nellist, who the Labour Party expelled in 1991. Addressing a meeting of political bedfellows in Coventry last month, Nellist is reported as having described the Labour Friends of Israel as "the enemy within". No doubt, in considering any application from Nellist to rejoin Labour, Corbyn and his brethren on Labour's NEC will wish to enquire whether this report is true and, if it is, what explanation Nellist can give for having uttered these words.

Corbyn may also wish to comment on the antics of a mob of anti-gentrification "warriors" that rampaged through London's Shoreditch locality on Saturday night last. Informed by a philosophy of greed and a politics of envy, it was organised (anonymously) via Facebook and claimed communities in London were being "ripped apart" by a variety of interests including "Israeli scumbag property developers".

I have no idea whether Israeli property developers have been redeveloping Shoreditch. But even if they have, and even if you consider gentrification to be a bad thing, why draw attention to the nationality of the developers? This is unadulterated racism. I suspect, however, that by "Israeli scumbag property developers" the author(s) actually meant "Jewish scumbag property developers" - but (being the cowards that they are) lacked the courage to say so.

I'm not associating Jeremy Corbyn with this attempt at mob rule. But I am challenging him to issue an unqualified condemnation not merely of what happened, but of the antisemitic language used. If Corbynism is to enjoy any semblance of legitimacy in Anglo-Jewish eyes, this is the least we can expect of Labour's new leader.