There's a terrible truth about this modern world we’ve forged.

Increasingly, we live in twin realities. Most of us - though a declining majority - see the world for what it is: a messy, ugly shambles, horribly disfigured by political failure. But we keep our fears and criticisms in perspective. Politics and the media may be flawed, but there’s no vast plot to enslave us, just failed systems, a profound lack of imagination, an acceptance of a rotten status quo, and the wrong people in the wrong jobs.

However, some of us - a growing minority - really do believe that politicians and the media, and in some cases doctors, nurses, teachers and police, are part of some all-encompassing evil scheme to take over the world.

Now, many might find this funny; so silly that all you can do is laugh. Perhaps think again, though, as quite a large number of conspiracy theorists increasingly favour using political violence to further their aims. Conspiracy theories have moved from joke, to nuisance, to part of the political landscape - especially among populists - to now being a security threat.

When societies find citizens breaking apart into two groups, which believe in completely different realities, then agony awaits. This doesn’t mean two opposing political camps - left-right, yes-no, progressive-traditionalist - it means two groups who quite simply share no common ground on truth, reality or fact.

Read more: Inside the QAnon cult as its contagion spreads to Scotland

Twin realities often mean violence. It’s what leads to revolution - from France to the American Civil War, from 1917 Russia to 1969 Northern Ireland, if societies are divided over what constitutes truth and reality, then fracture becomes almost inevitable.

We are, assuredly, not at that point. Yet. But across the western, developed world - in Europe, America, and the anglophone nations - there’s a growing coterie of citizens who share nothing in common when it comes to a collective outlook on life with fellow countrymen and women.

In truth, one group lives within a bizarre fantasy world, sometimes hard to distinguish from a form of mass mental illness, shared fever dream, or group hysteria; while the other looks life square in the eye, seeing reality for what it is: a hodgepodge of missteps and errors that sometimes end in good, but often end in bad.

The Policy Institute at King’s College London has just published extensive research into the British public, belief in conspiracy theories, and how conspiracies are disseminated.

Researchers found that among those who say they would take part in "direct action", linked to the conspiracy theories they believe in, most claim violence can be justified. For example, when asked if violence could be used at a protest against vaccines 34% said they strongly agreed, 30% tended to agree, 19% neither agreed nor disagreed, 1% didn’t know, 11% tended to disagree and 5% strongly disagreed. In terms of the overall population of Britain, 13% say violence could be justified.

These figures should terrify us. Let’s look at what the public at large believes. Around a third of us say various conspiracies are true. Will government use banks to control citizens? Thirty-five per cent say that’s either definitely or probably true. Are the media and government covering up information on terrorist attacks? Definitely or probably say 34%. Are "15-minute cities" a plot to limit freedom? Definitely or probably say 33%. Is the "Great Replacement Theory" - the racist trope that white people are being deliberately replaced by non-white immigrants - true? Definitely or probably say 32%. Was Covid a hoax? Definitely or probably say 23%. Did the UK Government carry out the 7/7 bombings? Definitely or probably say 19%. Did the Manchester bomb attack involve "crisis actors" pretending to be victims? Definitely or probably say 18%.

When it comes to where believers first came across conspiracies it’s often, unsurprisingly, online: YouTube, Facebook, Twitter and TikTok. Though increasingly, there’s a new kid on the block: The Light, a conspiracy ‘newspaper’ disseminated free in Britain.

Read more: What to do if you’ve got a coronavirus conspiracy theorist in the family

According to recent investigations by the BBC’s disinformation correspondent, Marianna Spring, The Light has “[shared] calls for trials and executions of politicians and doctors”. Journalists are also targeted. A recent article said “MPs, doctors and nurses can be hanged”. On the social media site, Telegram, the "paper" shared and endorsed content from far-right groups like Patriotic Alternative, “promoting rallies and posts talking about the ‘replacement’ of white people”.

The Light featured an article recommending the work of white supremacist Eustace Mullins, author of The Biological Jew and Adolf Hitler: An Appreciation. The Light defended the UK-based radio host Graham Hart over remarks he made calling Jewish people “filth” and suggesting “they deserve to be wiped out”.

The Light is linked to the German publication Demokratischer Widerstand (Democratic Resistance). Claims have been made that some Demokratischer Widerstand writers and a key donor met with the Reichsburger Group, which was behind a failed coup attempt in Germany last December.

So what we see is this: conspiracy theories are now deeply embedded in the public mind; a significant number of believers see violence as legitimate to achieve their aims; and conspiracy theories are becoming closely linked to extremism, especially far-right extremism.

Society is dangerously underestimating what’s happening. When the public is asked how widespread they believe conspiracy to be, we’re always wide off the mark. For example, the public thinks just 20% of Britons believe in the Great Replacement Theory. That seems pretty large. The reality, though, is 32% of us believe that conspiracy.

Read more: Tackling disinformation and extremism must start in schools

What do we do? Is there a solution? As history shows - in France, antebellum America, Russia, and Northern Ireland, to name but a few - once the twin reality schism opens up, it’s impossible to put the genie back in the bottle. History seems to have one trajectory.

If - god forbid - this fracturing of truth does indeed bear bitter fruit, then it is politics and the media which must carry the blame. Political parties and the media are the dual pillars of democracy. Politicians have traded in lies for years now - just think of Iraq. Those lies helped corrupt our shared reality. The media, most often, amplified political lies unquestioningly. That helped create the vacuum in society which has been filled by conspiracy theorists, some of whom, with ghastly irony, believe in executing politicians and journalists.