It’s a quicksand kind of feeling. The sensation that you’re flailing in space, with no purchase. Nothing to hold on to. That’s how our post-truth modern life feels sometimes, that nothing is real or to be trusted.

It was one of the things that most astonished me when I joined Facebook. I’d been on Twitter for a few years, where the people I interacted with were mainly other writers and journalists with broadly similar views to my own.

This was my “echo chamber”, my “safe space” where (back in 2011 at any rate) you rarely came across something deranged or offensive.

On Facebook, I did what everyone does – I accepted friend requests from people I vaguely remembered, distant relatives and so on.

And you’d notice, now and then, some of them would post stupidly offensive things, particularly around the time of Brexit.

Articles from dodgy-looking sources. Slightly racist memes. Well, that was all easily fixed with a couple of unfriendings.

But what about all the people who weren’t offended by the racist memes? Who liked them and who shared them with their friends?

The extent of Vladimir Putin’s worldwide political ambitions is rapidly, and breathtakingly, becoming apparent. No surprise, really. If you cast Putin in a film as “top international businessman who turns out to be a murderous drug baron”, audiences would be booing at the obviousness of it.

Vladimir Putin's role in Brexit hit the Daily Mail last week.

Anyone with half an interest in the subject has long been aware of the extent of his role in the election of Donald Trump.

But last week it was Russia’s part in helping to engineer Brexit that was the subject of a hard-hitting news piece.

Where, I hear you ask? The Guardian? The Morning Star? The Huffington Post? No. In that other famous left-wing journal – the Daily Mail.

They ran a story about how thousands of social media accounts dedicated to mocking Remainers and promoting Brexit originated from a “troll factory” in St Petersburg.

In the factory hundreds of Russian computer operators would work day and night on disinformation activities, everything from writing pro-Russia articles to simply posting tens of thousands of comments – all pro-Trump, pro-Brexit, anti-Clinton and anti-Remain – on YouTube, Facebook and Twitter.

On the day before the Brexit vote, Twitter accounts based in Russia posted 39,000 tweets in support of the Leave campaign before vanishing completely.

This Muslim woman was trolled online after the picture emerged.

Remember the infamous photo of the Muslim girl allegedly walking by one of the Westminster Bridge victims casually talking on her phone? The one that originated from an account describing itself as a “PROUD TEXAN AND AMERICAN PATRIOT”?

Except it wasn’t. It came from a Russian troll farm.

Twitter closed the account down but the image went around the world. There will be people out there now – even after it has been proved this was Russian propaganda – who still think it was real.

And what was the reaction of the Daily Mail’s readership to the news that Putin’s internet armies might have played a role in swaying their thinking?

I checked the Daily Mail’s message board, where they were saying things like this…

“It doesn’t matter what the Russians did or didn’t do, lots of people in the UK were fed up with being ignored by arrogant internationalists.”

“All I see here are desperate Remainers playing their last card!”

“My bike has a flat tyre – curse those damned Russians.”

That’s right – lots of Daily Mail readers didn’t like what their paper was saying. It’s rather like playing in a pig pen and then complaining about the smell.

But it was interesting to see that their responses broadly broke down into three camps.

1) Those who said: “So what if Russia did this stuff, it didn’t really affect the final outcome.”

2) Those who said: “This is all a ridiculous conspiracy theory.”

3) People who basically say: “We’ll never know.”

Did it affect the final outcome?

Imagine you’re – I’m sorry, there’s no other way to put this – but imagine you’re a bit simple minded.

You’re seeing the Leave campaign’s buses painted with their lie about giving £350million a week to the NHS and you’re believing that rubbish.

The Vote Leave bus promised an extra £350million a week for the NHS

Then you’re on social media in the run-up to the referendum and see posts about how bad the EU is, about how great it will be to leave.

Could this sway your thinking? Of course it could. Putin isn’t just doing this for a laugh.

But it is group three that the Russians are most interested in.

They know that there is an educated segment of the population who are wise to what they are doing and will never fall for their nonsense.

They know that there are people so stupid and racist that they are willing to believe anything put in front of them, so long as it panders agreeably to their prejudices: that Hillary Clinton is the devil, that the mainstream media are a bunch of lying liberals, that any attempt to stop the lunacy of Brexit is an attack on democracy etc.

But they know that the middle ground – group three – is malleable. That if you create enough noise and chaos and argument, then a significant number of people will throw their hands up and say, ‘There’s no way to know who’s telling the truth.’ That’s how Putin – a former KGB man trained in deception and disinformation – wins.

Then that other famous left-winger, Theresa May, said: “Russia has…mounted a sustained campaign of cyber espionage and disruption.

“We know what you are doing and you will not succeed.

“Because you underestimate the resilience of our democracies, the enduring attraction of free and open societies and the commitment of Western nations to the alliances that bind us.”

Except that’s all rubbish. Our democracies have been undermined. We’re leaving Europe. Our alliances are being torn apart. Trump’s base will love him even if it’s proved he was in the pay of the Kremlin. Alex Salmond is taking a job presenting a show on Putin’s official PR channel Russia Today.

You couldn’t make this stuff up. That horrible, vindictive, calculating, devious, ruthless little despot Vladimir Putin is playing us.

And he’s winning.