Nicholas Terry understands the internet’s darker side better than most. A history lecturer at Exeter University, Terry is an expert on antisemitism and runs a blog examining Holocaust denial and its dissemination online.

“You’ve got three separate phenomena converging,” he says. “One is the fake news stuff, promulgated by the likes of Facebook and Twitter, which is trying to promote specific false stories in real time for immediate impact; second, there’s the ideological bubble – people only reading leftwing or rightwing news sites; and then there’s this effort by fringe movements on Holocaust denial to make their websites look respectable and to hoodwink readers into thinking what they’re reading is OK.”

A particularly specious example of the latter is martinlutherking.org, operated by the white supremacist group Stormfront. Another is the Journal of Historical Review which, despite its name, is a Holocaust denial journal. “People think it is ‘legitimate’, which says more about the way they use Google to do research,” Terry said.

“They are plucking facts out of a web page that looks legitimate, but doing this so quickly they are genuinely surprised when they’re told afterwards they’ve cited a denier website.”

The challenges Terry faces in debunking myths, exposing lies and encouraging his students to question every click are now taking centre stage as a “tech-lash” mounts against the internet giants that a growing number accuse of having an excessive and unhealthy influence on our online lives.

Theresa May waded into the battle on Thursday, calling for investors to pull their funds from tech companies that fail to remove terrorist propaganda. “Investors can make a big difference here by ensuring trust and safety issues are being properly considered, and I urge them to do so,” May said.

Her comments came after Norfolk’s chief constable, Simon Bailey, accused the firms of “fundamentally enabling” paedophiles to abuse children.

Facebook, aware of the turning tide, has been trying to get on the front foot when it comes to addressing such concerns.

In a rare corporate mea culpa, Samidh Chakrabarti, product manager, civic engagement at the social network, last week published a widely shared article that acknowledged: “As unprecedented numbers of people channel their political energy through this medium, it’s being used in unforeseen ways with societal repercussions that were never anticipated.”

Addressing the role fake news played in the 2016 US election, Chakrabarti acknowledged that Russian posters had created 80,000 Facebook posts which had reached 126 million people in the US over a two-year period.

“We at Facebook were far too slow to recognise how bad actors were abusing our platform. We’re working diligently to neutralise these risks now.”

Significantly, it’s not just those who make or enforce the law who are at the vanguard of the tech-lash. Earlier this month, hedge fund Jana Partners LLC and the California State Teachers’ Retirement System pension fund warned Apple that iPhone overuse could be hurting children’s developing brains, an issue that, they said, threatened the company’s long-term market value.

Marc Benioff, the billionaire chief executive of Salesforce, a customer relationship management company, has gone further, calling for firms that peddle “addictive” technology to be regulated like big tobacco. Otherwise, he warns, there will be toxic consequences, similar to those that followed the bursting of the credit bubble in 2008.

“A decade ago you had the banks talking about collaterised debt obligations and credit default swaps, saying they were great for the economy, but regulators weren’t paying attention,” Benioff told a Davos audience last week. “The government needs to come in and point ‘True North’.”

The credit bubble analogy is apposite. The anger trained on the banks following the credit crisis is migrating towards the largest tech firms, who stand accused of behaving like monopolies.

Sir Martin Sorrell, boss of the advertising giant WPP, warns that the forces that powered Donald Trump’s election in America and the vote for Brexit stem partly from fears about the societal challenges posed by technology. “A large reason for the rise of populism on both sides of the Atlantic surrounds ... issues around privacy and certainly about jobs, and how the economy will develop at a time when technology is becoming increasingly important,” he said.

It is a rare moment in history when politicians and chief executives are aligned.

“The threat to the tech giants is coming from both worlds simultaneously, and the one feeds on, and takes support from, the other,” said Barry Lynn, executive director of the Open Markets Institute, an organisation that raises awareness of the political and economic dangers of monopolies.

“Benioff and Sorrell are not outliers,” insisted Jonathan Taplin, director emeritus at the Annenberg Innovation Lab at the University of Southern California and author of Move Fast and Break Things: How Facebook, Google and Amazon Cornered Culture and Undermined Democracy. He points out that Facebook and Google took 88% of all new online advertising dollars last year. “Internet monopolies distort markets and political systems,” he added. This awareness seems set to make 2018 the year when it becomes apparent that big tech has become too big to defy gravity.

“Perhaps we’re at an inflection point where we stop getting more and more ecstatic about our tech champions and instead become realistic about the fact that they are for-profit companies like so many before them,” said David Autor, professor of economics at the Massachusetts Institute of Technology.

“They create some great products, which is awesome. But their interests are not intrinsically civic-minded. I don’t fault them for that. But it’s the responsibility of government, competition policy regulators and attentive citizens to ensure that these important non-state actors have the incentive to behave ethically.”

But how? Few back the nuclear option: a break-up similar to the pre-millennium attempt to separate Microsoft’s Windows suite of applications from its Internet Explorer web browser.

An alternative is the anti-monopoly treatment meted out to US telecoms giant AT&T, which in 1956 was forced to license its patents to rivals for free. The result was a technology explosion out of which emerged hundreds of innovative companies that became the first inhabitants of Silicon Valley.

“Anti-monopoly enforcement leaves the basic services largely intact but actually limits the power of the monopolist in ways that eliminate the political dangers of concentrated power while improving the service that the customer will receive,” Lynn said.

Such an approach would surely win favour with George Soros. “They claim they are merely distributing information,” the financier told a Davos audience last week. “But the fact that they are near-monopoly distributors makes them public utilities, and should subject them to more stringent regulations aimed at preserving competition, innovation, and fair and open universal access.”

In the US, where many of the tech giants are based, a Trump administration elected on the promise of tax cuts and deregulation is unlikely to have an appetite for such measures.

Europe sees things differently. The European Commission’s decision last year to fine Google $2.4bn (£2.14bn) for favouring its own services when consumers were using its search engine suggests an appetite for action.

But politicians and regulators risk falling out of step with consumers if they push too hard. Amazon customers may mourn the loss of their local bookshop but they still use its Prime service. Most Londoners don’t want Uber banned from the capital.

And the services offered by the likes of Facebook are free, a fact that neuters one of the more potent charges against established monopolies – that they push up prices.

In the current lacuna, a more practical approach to curbing the tech giants has started to emerge by focusing on what they prize most. Data is crucial to the development of artificial intelligence, the technology that allows the giants to anticipate our every whim and to sell us a new range of services we don’t yet know we need. But few consumers appreciate its value.

“Consumers are giving away valuable personal data for free,” Taplin said. “As they say, ‘When the product seems free, you are the product’. The average teenager works two hours a day for [Facebook co-founder] Mark Zuckerberg, without getting paid a dime.”

The launch of European Union-wide data protection rules in May has already forced Facebook to “protect free expression, keep people safe, and respect privacy”, according to the company’s chief operating officer, Sheryl Sandberg. The other giants will have to follow suit. A recalibration is looming.

Germany is already threatening to ban Facebook from making access to its platform conditional on it being allowed to harvest unlimited amounts of user-generated data from third party websites. Facebook’s response will reveal much about how it and, by proxy, the other giants, intend to resolve the inherent tension between their insatiable appetite for data and the consumer’s desire for privacy. As they are forced to adjust their business models, others may spy opportunities.

“People use Facebook because other people use Facebook,” Autor said. “Which means that if enough people decided that something else was better, Facebook could very quickly lose market share. Unrealistic? Perhaps. But think of Friendster, MySpace, AOL or Yahoo. These tech monopolies are often far more contestable than we assume.”

Ultimately, the greatest threat to the tech giants isn’t from politicians or regulators or rival corporations. It’s from themselves.

Warning shots

“Google, Apple and Amazon have created disruptive technologies that changed the world, and they deserve to be highly profitable and successful. But the opportunity to compete must remain open for new entrants and smaller competitors that want their chance to change the world again” Massachusetts senator Elizabeth Warren

“Social media companies deliberately engineer addiction to the services they provide. This can be very harmful, particularly for adolescents. There is a similarity between internet platforms and gambling companies” George Soros, billionaire philanthropist

“I don’t have a kid but I have a nephew that I put some boundaries on. There are some things that I won’t allow; I don’t want them on a social network” Tim Cook, Apple CEO

“We have to take our democracy back. We cannot leave it to Facebook or Snapchat or anyone else. We have to take democracy back and renew it. Society is about people and not about technology” Margrethe Vestager, Europe’s commissioner for competition

“God only knows what it’s doing to our children’s brains” Sean Parker, Napster founder, on Facebook