Two conspiracy theories have gained prominence in recent weeks, one of which has been spread by prominent pro-Brexit figures on the right and another by influential figures on the left. One is about the Jewish philanthropist George Soros while the other concerns the charity Oxfam.

Soros has been accused from various quarters of pushing a "secret plot" to undermine democracy. Meanwhile, it has been implied by some on the left that Oxfam , which is embroiled in a scandal in which aid workers are accused of paying for sex with impoverished Haitians, has been targeted primarily because the right-wing media have a hidden agenda.

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Both are conspiracy theories (broadly speaking) and both reveal something disconcerting about the road down which British politics is currently travelling. As Adam Barnett has written for Politics.co.uk, the "main point of interest in the Telegraph's recent attack on George Soros is not whether its authors are antisemitic, but what it tells us about the growth of the paranoid style in British politics". As Barnett correctly goes on to say, "the notion of a hidden power pulling strings has become increasingly popular".

The question is – why?

Broadly speaking, grand conspiracy theories are an instrument with which the individual can feel his or herself absolutely at the centre of world events. This is presumably an experience akin to that undergone by members of religious or political cults: one has access to a truth inscribed in sacred texts which other less fortunate souls lack. Thus Arthur Koestler described his communist faith as the whole universe falling into pattern "like the stray pieces of a jigsaw puzzle assembled by magic at one stroke".

Not all conspiracy theories are like this; though it is worth keeping the point in mind as they gain increasing traction in our digital age. When events can appear to career from one crisis to the next, there is an obvious appeal to theories which purport to put social phenomena back into neat little boxes.

But the two conspiracy theories in question cannot be satisfactorily explained away in this fashion. Conspiracy theories about George Soros in particular sit within a wider resurgence in populism, which depends on the existence of 'in' and 'out' groups and a paranoid style of going about politics.

Put another way, populist movements derive their strength from the groups which stand in opposition to them. In the words of the Argentinian theorist and proponent of left-wing populism Ernesto Laclau, every identity "depends on an outside which both denies that identity and provides its condition of possibility at the same time".

Within left-populism, this manifests itself through a dichotomy such as the "oligarchy" versus the "99 percent". Its right-wing equivalent posits "the people" against "saboteurs" and "cosmopolitans". Both populist styles are fond of rallying against 'elites' and the 'establishment', though it is important to emphasise that there isn't necessarily a moral equivalence between populism's various incarnations – not all forms of populism are equal.

It isn't particularly hard therefore to see how a wealthy Jewish businessman might find himself instrumentalised by a certain type of populist thinking. The 'in' and 'out' dynamic must after all be constantly replenished, as is observable in countries where populist regimes actually hold power, like Venezuela and Hungary. Capitalism is defined not as a system, but in terms of 'good' and 'bad' individuals – the Bilderberg Group, the Jews, the Gringos, saboteurs and traitors etc. These categories must be constantly expanded by populist regimes in power because they inevitably find that their problems are not solved by the elimination of the primary 'out' group.

I'm digressing slightly but my broader point is that certain conspiracy theories are gaining traction because the populist style is making headway. It is easy to performatively overblow some of this stuff, but it ought to be apparent that the populist method of doing politics can descend quite quickly into authoritarianism and, dare I say it, fascism. There are plenty of gloomy historical precedents for this trajectory at any rate.

Other societal developments invariably play a role in the spread of conspiracy theories. Postmodernism – with its notion that we are all entitled to our own solipsistic 'narrative' – has an influence I suspect. When Michael Gove declared boorishly in 2016 that the British public had "had enough of experts" he might have been some slick bien pensant professor smugly declaring that there are 'no such things as facts, only theories'. If you tell people that 'experience' is everything they may take you seriously – and their experience might be quite different to your own.

All of that said, conspiracy-mongering about the right-wing press and its investigation into Oxfam can perhaps be dismissed with a more prosaic rejoinder: you really can't help people (or newspapers) being right for the wrong reasons.