The sudden rebranding of CCHQ’s Twitter feed as a fact-checking service, at the start of the debate between Boris Johnson and Jeremy Corbyn, was no simple one-off stunt. It was merely the first step-change in a Conservative election campaign designed around organised lying.

For the first three weeks, compared to a traditional campaign, Tory strategy seemed defocused. They monotonously vowed to “get Brexit done”, and tried to stigmatise Corbyn, but refused to advance many substantial promises of their own. But the real strategy was contained in the lies.

The first was the assertion that Labour plans to spend £1.2trn. Without any evidence, the “calculation” by Tory central office was nevertheless splashed across the right-wing newspapers. Next came the assertion that Labour plans to turn the NHS into a four-day-a-week service. This was extrapolated from the party’s long-term promise of a four-day working week to NHS staff, but has “landed” so well in Conservative circles that its mere mention triggered groans from the selected right-wing Tories in the audience last night. It is, of course, completely untrue.

Look at the leaflets handed out by former Tory leader Iain Duncan Smith in Chingford and you can see a whole barrage of lies: “The Labour Party want to allow uncontrolled immigration, to give foreign nationals the right to vote and free access to the NHS and to welfare benefits,” one states. The 40 new hospitals was a lie. The 20,000 extra police figure is a lie. And as veteran journalist Peter Oborne has documented, the modus operandi of Boris Johnson himself is lying by reflex. But all this is just for starters.

Isaac Levido, the Lynton Crosby protégé who masterminded the Australian right’s victory over the opposition Labor Party in June, and is running the Tory campaign, is adept at the use of “front” Facebook publications to channel disinformation to target groups. The Guardian documented how Crosby's company, CTF, ran disinformation campaigns for clients: first, innocuous Facebook pages are set up, posting legitimate news articles to build an audience around a subject. Then the pages are promoted using Facebook ads. Finally, at a decisive stage, these pages are flooded with posts from activists, designed to resemble a grassroots movement of outrage over an issue damaging to your political opponent.

If CCHQ are following this playbook now, we should expect the small and ridiculous lies of the past couple of weeks to be suddenly replaced with big and serious lies. Where these might come from is already apparent. On the WhatsApp channels of supporters of the Hindu nationalist BJP party, there are already sectarian slanders circulating on an industrial scale.

One Labour candidate has found memes circulating in Conservative-supporting social media networks containing a gross caricature of a migrant, captioned “they're like sperm, only one in 1,000 works”. In essence, “shitposting” culture on the British right is strong, dynamic, and continuously boosted by shares and new content from the US far right.

It's important to understand here the desired effect, and what can be done to counter it. All professional disinformation strategies follow the principle of the “evil doctor”. A good doctor looks at a patient and says: dodgy heart, faulty hip, overweight... how do I make it better? An evil doctor looks at the same symptoms and asks “how do I make them worse?”

Labour, like all parties, has symptoms an adversary can “make worse”. Corbyn's failure to deal quickly enough with anti-Semitism cases among Labour members; the imposition of bizarrely mismatched candidates on marginal seats; the emergence of sectarian battles from the Indian subcontinent inside some local parties.

Then there are more strategic problems. Labour seems determined to cost its spending pledges to the last penny, against specified taxes and borrowing. Thus, it perpetually has to battle with neoliberal institutions like the Institute for Fiscal Studies, which simply do not recognise the growth-multiplying effects of public spending. So when the manifesto comes out tomorrow, the Conservatives will replace the £1.2trn lie — which Johnson already dropped in the debate — with a new lie about a “black hole” in Labour's spending plans.

But perhaps the biggest weakness of all is beyond Labour's control. There is a significant cultural mismatch between the party’s activists and MPs, and the socially conservative culture of some older voters in seats the Conservatives are targeting. I expect the Tories to ruthlessly exploit this, and in a targeted way. Unless you live in a northern English town, and are over the age of 45, don't expect to see the most blatant lies and fabrications. And they won't be traceable to the Tories. But if you do live in these, and other Tory targets, the experience of the Australian election means we should expect a deluge of outright false information.

I'm not talking here about the polite xenophobia of a candidate like Duncan Smith quoted above: I am talking about the “migrant rape” memes, the targeted paedophile rumours aimed at gay MPs, fake news stories about Sharia law, gypsies and transgender people. These stories will never be traceable to a mainstream party; and may indeed be manipulated from outside.

In the Australian election, observers noticed that the Chinese microblogging site WeChat was, in the days before the vote, rife with alt-right propaganda about Australian Labor, including claims that it would force schools to teach children how to have gay sex, and a fake quote from Labor leader Bill Shorten saying “immigration from the Middle East is what Australia needs”. This spread, via the Chinese expat community, into the social media ecosphere of the right's target seats.

Unfortunately the defences against late stage, mass, targeted disinformation are untried. But we can make a start. The most important thing at this stage is to insist broadcast journalism follows its basic professional standards and exposes outright lies. The BBC and others have begun both fact-checking political claims and monitoring political ad-spend — but that's not enough.

Journalists are trained to say: “here is the truth”. Few are ready to prioritise saying: “this is a lie”. Indeed, when the Conservatives temporarily rebranded their Twitter account as a fact-checking site, provoking a backlash from other parties and a cease and desist warning from Twitter, the BBC’s most senior political journalist, Laura Kuenssberg, tweeted: “This seems like a really daft row to pick”. Oborne reports that senior BBC executives told him it was “wrong to expose lies told by a British prime minister because it undermines trust in politics”.

There is in broadcasting, rightly, a culture of covering the policies and the issues first, the ephemera and the spats second. But organised lying is not a spat, or tit-for-tat — if one party is doing it and the other is not, that's the main story. With the tabloid press so allergic to facts and balance that, in the case of the Daily Mail, it is delisted as a reliable source on Wikipedia, the broadcasters are a vital front line in the defence of truth.

A second defence line will be vigilance. There will come a moment when the little lies become big ones, and at that moment — on the jiu jitsu principle — every effort must be made to turn the strength of the enemy against them, by refuting the lies and tracing the source of them. “We're being lied to” is one of the strongest suspicions in working class culture, going back to the days of the Boer War and the Somme. In the case of the latter, the simple contrast between the newsreel footage and what soldiers wrote, and what they said on leave, was enough to stoke mass anti-war sentiment.

The third antidote is face-to-face contact. The Conservatives, right now, do not have a vast army of activists and Labour does. What's more, thanks to Momentum and its advisers from the Bernie Sanders movement, Labour has multi-layered and deep professional operations to put human faces onto doorsteps in vast quantities.

The Tory campaign is not really digital first: it is the broadcast lie first, the digital amplification of it second, and the bloke down the pub telling everyone the candidate’s a pervert third. So the fightback has to be multilayered: hold the broadcasters to their own rules; trace the origins of online lies; and promote patient conversations between human beings in every public space.