One of the wilder conspiracy theories I have seen was in a neo-Nazi newspaper in the mid-1990s in Moscow. The article revealed that Boris Yeltsin and Mikhail Gorbachev were both assumed names and that the men had been born Baruch Yeltzer and Mikhail Solomonovich Gorbachev (his real patronymic is Sergeyevich). In other words, the architects of Russian misery after the collapse of the Soviet Union were secret Jews.

This was outlandish even by the standards of eastern European antisemitism. It was also hypermarginal in the media. You had to buy pamphlets on the street to read about plots to dilute the purity of the Russian race by a cabal of Jews/Zionists (the two words were interchangeable). Then came the internet. These days you are never more than a couple of clicks away from weapons-grade antisemitism.

But it still comes as a shock when one of the oldest and most versatile themes of the genre – the Jewish financier, dandling politicians on puppet strings, coordinating events in the shadows – finds its way on to the front page of a national British newspaper.

To be clear: I am not charging any individuals at the Daily Telegraph with willingly promoting hatred of Jews or writing with that agenda in mind. I have no idea what went on in the heads of the people who wrote this morning’s splash headline: “Man who ‘broke the Bank of England’ backing secret plot to thwart Brexit”. Nor do I know what discussions went on in the newsroom as they laid out the pages and assembled the package to include accounts of George Soros’s financial involvement in the politics of other countries.

That copy includes the observation that his foundation is “accused of toppling governments in Georgia and Ukraine” and that, while he denies the allegations, not everyone is convinced that Soros’s Open Society Foundation (OSF) is the philanthropic promoter of liberal values it professes to be. His denials, the Telegraph notes, have “not stopped the OSF being banned from Russia and Uzbekistan”. As if the autocratic regimes in Moscow and Tashkent need real provocation to obstruct civil society organisations.

A reader might well infer that there is something of the night about this Soros character; no smoke without fire

From this, a reader might well infer that there is something of the night about this Soros character; no smoke without fire. Besides, what is this foreign man, who once made a packet trading against the mighty sterling, doing sticking his nose into Brexit? And, of all things, in “secret”, in the shadows, where svengalis lurk. (Although in reality Soros’s interest in the remain cause was publicly available knowledge.)

Nowhere does the Telegraph say that Soros is Jewish. But to a particular audience – to those whose antennae are attuned to the high-frequency signal – it goes without saying. That is the subtext, and often the actual text, in officially sanctioned, orchestrated attacks on Soros in Poland, Hungary (where he was born), and other eastern European countries. He has earned this opprobrium by supporting, via Open Society, liberal politics and by resisting authoritarian measures that corrode the rule of law and stifle political pluralism.

To the radical nationalist governments in those countries he has become the arch bogeyman. And a vintage bogeyman it is, too: the all-powerful internationalist Jew with no organic connection to the soil of nationhood; the embodiment of demonic, wandering, predatory capital; the new uber-Rothschild. Soviet propagandists called Jews “rootless cosmopolitans”.

Soros’s name turns up in far-right protests across the former eastern bloc, but also in the US, where he is a hate figure for Trumpian ultras. He has been accused of paying for anti-Trump protests. He has been accused of meddling in the US election. He has been accused of trying to dilute Christian white culture in Europe by orchestrating influxes of Muslim refugees. And now he is accused by the Daily Telegraph of conspiring against Brexit. A busy man indeed.

The fact that Soros is supporting an anti-Brexit movement is newsworthy. It was reported in the Guardian, but not draped in the idiom of conspiracy. The details of Soros’s involvement, unpacked at length in the Telegraph, make valued reading for the kind of person who is interested in that sort of thing. Some are more interested than others. Nigel Farage was quick to tweet his gratitude to the Telegraph for helping, at long last, to expose the Soros scourge.

I don’t expect the Telegraph, finding itself in possession of material of interest to its audience, to do anything other than publish it. What I might have expected is that someone, somewhere in the organisation might be sufficiently literate in European history and attentive to what has been going on in the rest of the world to understand the wider cultural context of this material. The main author of the story is Nick Timothy, former joint chief of staff to Theresa May. Perhaps he might have wanted to ensure that his journalism was being handled in ways that would not leave him vulnerable to the charge of riding a global antisemitic meme. He has vigorously denied any such intent in the aftermath of publication. I don’t know when he realised this might be an issue – how loud the clamour had to be to resonate in his tin ear – and nor, in all honesty, do I care much.

What I care about is the whole package. There is no one specific line or picture or adjective or omission that can be held up as cast-iron proof. There is no single moment where the line is crossed. There is no clause or adjective from which the antisemitic smoke rises as from the barrel of gun. And yet a modicum of cultural awareness and a glancing acquaintance with old Jew-hatred and its modern iterations would have alerted a half-decent editor to the signal being sent by that front page. In case there is no such person at the Telegraph to decrypt that signal let me spell it out for them. It was this: shadowy Jew-financier conspires against Britain. That might not seem obvious to many readers. It might even sound a little paranoid. But I am very confident that two audiences understood it instantly and very clearly in exactly those terms. One was antisemites, the other was Jews. The first group cheered, the second recoiled in horror. And of that shameful negligence, oh, Daily Telegraph, j’accuse.

• Rafael Behr is a political columnist for the Guardian