Thank you for that kind introduction, and thank you for the invitation to speak at the Oxford alumni festival, a most prestigious gathering.

From the day I graduated from Teddy Hall, in the summer of 1978, I have been in the news business.

My father, Frank, left school at 14 and started as a copy boy at the Leeds Weekly Citizen. He later made it to Fleet Street and a top job at the BBC World Service.

Frank Barber spawned a family of journalists, all of whom went to Oxford. My twin, Stephen, is a banker and inveterate letter writer to newspapers. My brother Tony joined Reuters and the Independent and now works at the Financial Times.

My own journey into journalism was more circumspect. At Oxford, a young man by the name of Mark Thompson rejected an article I had composed for Isis magazine. Now I understand why people complain about editorial bias at the BBC.

The Barbers have always considered journalism not just as a profession but as a vocation. To be employed as a journalist is a privilege but it also confers a special obligation: to attend to the facts and to pursue the truth.

This is why I am so concerned about the rise of fake news. We’ll come to definitions in a minute. For the moment, let me say this:

Fake news damages public trust in news media.

Fake news undermines public confidence in our democratic discourse.

Fake news exacerbates economic pressures facing quality news organisations.

Finally, and perhaps most importantly, fake news highlights issues of responsibility and regulation in our fast-evolving media ecosystem.

Now, fake news is hardly a new problem. As my old colleague John Lloyd, co-founder of the Reuters institute here at Oxford, wrote in the literary pages of the weekend FT earlier this year: “Lies, seduction, persuasion, flattery, and hypocrisy have always attended public life; alternative facts and fake news have been part of the feedstock of politics and journalism for centuries.”

My own fake news item of choice comes from ancient Rome: the dodgy dossier obtained by Octavian which he used to discredit his imperial rival Mark Antony.

Octavian claimed that a document in his possession was Mark Antony’s last will and testament. It appeared to confirm that Antony intended to leave legacies to his three children with Cleopatra, queen of Egypt. These gifts included large pieces of Roman-held territory in the Mediterranean. Octavian made the document widely available by persuading the Senate to issue a decree that was posted in the Forum. It was later dispatched via messengers throughout the empire. Not quite as effective as social media, but still a successful political stitch-up, circa 33BC. The rest, as the future Caesar Augustus might have said, is history.

Let me clarify one matter: fake news is not the same as mistaken reporting or lazy journalism that requires correction. Matthew D’Ancona has it right in his new book, Post-Truth. Fake news is the deliberate presentation of falsehood as fact. Now the motivation may be political influence or financial return — or both.

My last example is literary: Honore de Balzac’s denunciation of the trade of journalism in his great novel Lost Illusions. Written between 1837 and 1843, the novel portrays theatre reviewers as hired assassins and actresses who pay for disparaging write-ups because: “Silence is what they fear most of all.” Polemics, laments one young writer, build a pedestal for celebrities.

What makes the pernicious phenomenon of fake news qualitatively and quantitatively different from the past is that technology — via search engines and social media platforms — has offered an unprecedented opportunity to spread it in real time and at scale.

The world had a foretaste of the power of modern technology in harness with fake news early last century.

On the evening of October 30 1938, a young actor and future director, Orson Welles, broadcast The War of the Worlds, an episode in the American radio anthology series The Mercury Theatre on Air.

The episode was an adaptation of HG Wells’ science fiction novel The War of the Worlds. Welles’ production became famous — correction, infamous. As narrator he used a news bulletin format to report a Martian landing in New Jersey, culminating in an invasion of New York. The radio broadcast that Sunday evening triggered hysteria and, some say, mass panic. Whatever the precise size of the programme’s audience, the subsequent controversy secured Orson Welles’ future as a dramatist.

Orson Welles in 'Citizen Kane' (1941) © Getty

Sadly, today’s fake news equivalents lack the bravura and imagination of the man who later directed and starred in the movie Citizen Kane, a great movie incidentally about the newspaper business; but what these so-called news reports miss in style, they fully make up in reach.

Take, for example, the non-existent Denver Guardian which published a story on the suicide of an FBI agent suspected of leaking Hillary Clinton’s emails. It was shared up to 100 times a minute on Facebook.

Another case involves “Pizzagate”, the conspiracy theory that there is a global paedophile ring involving senior Democratic politicians, a set of food-related code words and a string of pizza parlours.

People who self-identify on the right are three times as likely to mistrust the media as those on the left

Edgar Maddison Walsh, a 28-year-old father of two, was arrested in Washington DC last December after firing an assault rifle into a pizza restaurant. Court documents said that as a concerned father he decided to drive six hours from his home to the restaurant and investigate himself (naturally shooting first and asking questions later).

And here’s the killer fact about Pizzagate: a survey from YouGov and The Economist found that 17 per cent of Hillary Clinton supporters and 46 per cent of Donald Trump voters believe elements of the bizarre conspiracy theory are actually true.

So what is going on?

First, I believe the rise of fake news reflects a general decline in the terms of political debate and a related erosion of public confidence in our institutions.

Right now, the environment is uniquely conducive to fake news because:

We live in a world where there are no accepted facts.

A world where facts are secondary to opinion.

A world where the media landscape has fragmented.

A world which has become intensely polarised.

Hillary Clinton after the election in November last year © Reuters

This is particularly true in western democracies, especially America. People who self-identify on the right are three times as likely to mistrust the media as those on the left (because they feel they are not represented).

At the same time, it is instructive to ask people if they trust their own sources of news.

Users of the Fox News and the Washington Post had similar scores of 53 per cent, according to Nic Newman who presented this year’s Reuters Institute’s Digital News Report.

Second, we are witnessing the consistent advancement of what might politely be described as alternative facts. President Trump himself is the arch exponent.

The New York Times has published a definitive guide to Mr Trump’s falsehoods, including outright lies or demonstratively false statements, as well as a broader list covering exaggerations or misleading statements. It is staggering in its frequency and range.

Now every president has shaded the truth or told occasional whoppers, but there is no obvious precedent for the US commander-in-chief, the nominal leader of the democratic west, to spend so much time on the wrong side of the truth.

Outright falsehoods range from Mr Trump’s position on the invasion of Iraq (He was for, then he was against it); the murder rate in America; the vetting of immigrants to the US; and the charge that President Barack Obama ordered his campaign HQ to be wiretapped, where there is no evidence to support such a claim.

Perhaps Mr Trump’s most serious untruth is that “millions of people” voted illegally in the 2016 election, a charge that directly challenges the legitimacy of the electoral system which put him in the White House.

US President Donald Trump © Matt Cardy/PA Wire

And yet: this is the same individual who virtually every day on Twitter or live TV accuses the mainstream media such as the New York Times, CNN and the Washington Post of fake news.

Mr Trump’s war on the media makes Richard Nixon’s tactics look tame by comparison. His goal is to neuter the independent journalism which offers one way — to be sure, not the only way — to hold power to account.

In so doing, Mr Trump offers succour to all the likes of Messrs Erdogan and Putin whose world views are directly antithetical to the principles of free speech and pluralism which America has defended for more than 200 years.

(I should add for the record here that President Trump was a good deal more courteous when I interviewed him earlier this year in the Oval Office, with two FT colleagues).

“Thank you for making time to see the FT, Mr President,” I said, by way of introduction.

“That’s OK,” replied Mr Trump, “you lost, I won.”

Now, before we become too complacent here in the shadow of the dreaming spires, let’s not forget the pack of lies and half-truths which the Leave and Remain campaign propagated during the Brexit referendum campaign.

By my tally, the Leavers pursued the most egregious falsehoods.

The £350m weekly savings from Britain’s budget contributions to the EU, to be reallocated to the National Health Service.

(No mention of the likely €50bn-plus net bill to settle our obligations once the UK concludes divorce proceedings with Brussels.)

Or the charge — by Leavers — that Turkey was about to join the EU, letting loose a flood of migrants into the UK.

Technology has vastly empowered individuals via the dissemination in real time of news, data and moving image. Everyone has a voice.

Remainers were not much better. Inspired by George Osborne’s Treasury, they ran a series of scare stories about the UK economy dropping off a cliff in the event the government lost the case for staying in the EU.

(Now, Brexit may still inflict a heavy cost on the economy, but as we now know: not overnight. Putting sole emphasis on the economy rather than the political case for membership was also misleading and misguided. but that’s another story . . .)

The third factor in the rise of fake news is the fragmentation of news media. This is a phenomenon which I have witnessed first-hand since I became editor the Financial Times in 2005.

One of the relatively few things I share in common with Rupert Murdoch, whom I once worked for, is a love of print journalism. I like the feel, the serendipity of discovering interesting news and views in a well-designed, well-written newspaper.

And I don’t happen to believe that print will disappear anytime soon, at least among established and trusted brands like the FT, New York Times, Wall Street Journal and Washington Post.

But the fact is that newspapers have been in decline for at least a decade, and the trend is only likely to continue, driven by the digital revolution.

The internet has dramatically lowered the barriers to entry in modern media and that has led in turn to dramatic shifts in consumer reading habits.

Newcomers such as Axios, BuzzFeed, Politico, Twitter and Vice Media have created new forms of storytelling. Others such as Ezra Klein’s Vox and Bill Keller’s Marshall Project specialise in political data analysis and monitoring of the US justice system.

Technology has vastly empowered individuals via the dissemination in real time of news, data and moving image. Everyone has a voice; everyone has the potential to be a citizen journalist.

But technology has also flattened the digital plain, creating the illusion that all content is equal. It has made it possible for everyone to produce and distribute content that looks equally credible. And when people think all content is equal, they assume that it’s equally biased or credible. Their distrust encompasses everything they disagree with. Facts no longer matter in this parallel universe of alternative facts.

So what do I mean by this parallel universe?

Here is Scottie Nell Hughes, a Trump supporter and CNN commentator during last year’s presidential campaign. “So one thing that’s been interesting this campaign season to watch is that people say facts are facts — they’re not real facts. Everyone has a way — it’s kind of like looking at ratings or looking at a glass half-full of water. Every body has a way of interpreting them to be the truth or not true. There’s no such thing, unfortunately, any more, as facts.”

Scottie Nell Hughes © Getty

Well, unfortunate is certainly one way of putting it . . .

What Ms Hughes has correctly identified are “filter bubbles”, self-reinforcing information channels made all the more dangerous when that information is false or inflammatory, that is to say, fake news.

Now, the news business has always catered to different cohorts of readers, often with opposing political points of view. Think Daily Telegraph and Guardian. And fragmentation leading to polarisation goes back 30 years when the US government deregulated cable TV, offering an opening which Rupert Murdoch and Roger Ailes brilliantly exploited with the launch of Fox News.

The key point to grasp today is the way the new ecosystem of digital media distribution has encouraged these self-reinforcing channels to flourish,

In the UK, almost 30 per cent of people use Facebook as a news source, according to the 2016 Reuters Digital News Report.

That figure is growing, and is heading toward the 40 per cent of US adults who use Facebook as a news source, according to a Pew Research report in 2016. Overall, some 62 per cent of American adults access news on social media.

Yet these networks are deeply flawed news outlets. According to a BuzzFeed News analysis, engagement with fake news on Facebook increased dramatically in the final three months of the campaign.

Overall, some 62 per cent of American adults access news on social media

Top performing election-related news stories on Facebook generated more engagement — loosely defined via social media — than the top stories from major news outlets such as the New York Times, Washington Post, Huffington Post, NBC News and others.

US intelligence agencies have evidence, too, that Russia, using thousands of covert human agents and robot computer programmes, spread disinformation referencing the stolen campaign emails of Hillary Clinton, amplifying their impact exponentially.

This is the subject of separate congressional and independent counsel investigations into Russian interference in the US election which includes the bombshell question: did the Trump campaign actively collude with the Russians in the sabotage operation?

Regarding the 2016 campaign: Mark Zuckerberg, Facebook’s chief executive, has argued that the scale of fake news has been exaggerated, amounting to less than one per cent of what people actually see in the Facebook news feed.

But this misses the point. While the scale may be debatable, the sophistication of the fake news operation is not.

Sensational stories are now being crafted to maximise audience and traffic. Data analytics are being deployed to identify the subjects and themes that appeal to thousands of subgroups according to defining characteristics such as religion, political beliefs or taste in TV shows and music.

Algorithms can determine these groups’ hot-button issues and identify “followers”, pinpointing those most susceptible to suggestion. The network effect allows the news generator to capitalise most effectively on the scale, distribution and sharing systems provided by Google, Facebook and other platforms. Equally important is the role of “Bots” — automated systems designed to imitate people — which have become a powerful force in driving the fake news phenomenon.

Now, the quality of the most popular Facebook fake news items leaves plenty to be desired:

“Woman arrested for defecating on boss’s desk after winning the lottery”, courtesy of thevalleyreport.com with 1,765,000 shares, comments or likes.

Or try this, courtesy of empireherald.com, “Cinnamon Roll Can Explodes inside Man’s Butt During Shoplifting Incident”. This garnered 765,000 comparative shares and likes.

I agree: sharing is not believing.

But what compounds the problem is the way audiences — and therefore ad revenues — have shifted from print to digital platforms. An estimated 90 per cent of all new digital advertising goes to Google and Facebook, according to Digital Content Next, the media trade group.

Big Tech has achieved an unprecedented dominance in the advertising market, once the lifeblood of newspapers and news organisations.

Now, the FT is the first to tip our pink hat to innovative technology and new business models. Newspapers who failed to adapt to the digital revolution faced a choice: adapt or die. The FT survived — and thrived.

Over the past 10 years, we transformed our own business model, charging for content, raising prices and building a subscription business which allowed us to steadily reduce our dependence on ad revenue.

As a result, we have now developed a base of digital subscribers which accounts for more than 75 per cent of our worldwide readership of 870,000. And advertising revenues account for less than half of our overall business.

Yet the stark fact is that the new media ecosystem is far from a level playing field — either from a regulatory or commercial standpoint. Fake news highlights and exacerbates the problem.

Sensationalist stories manufactured by fake news operators capitalise on the automated advertising monetisation platforms provided by search and social media — and they divert revenues from real publishers.

As the FT wrote in evidence earlier this year to a parliamentary committee investigating the fake news phenomenon: “It creates a Gresham’s Law for media — with bad stories forcing out the good and funnelling scarce advertising to fake news producers.”

What sticks in the collective craw is that news publishers — especially in the UK where the libel laws are far more onerous — bear the considerable expensive and risk relating to accuracy and fairness in the post-Leveson era.

As my one-time Oxford nemesis and now good friend Mark Thompson argued in a speech in Detroit this year: in professional news organisations, you can see who wrote the story and if you think it’s inaccurate or biased, you know who the editor is, and the publisher.

Mark, now CEO of the New York Times, added, pointedly: with the social media platforms and grand aggregators like Facebook and Google, “the ultimate provenance of content, and the algorithms that decide what we see and don’t see, lack this clarity.”

So what is to be done about the fake news phenomenon and the collateral damage to quality journalism?

First, the dominant technology sites must recognise they need to take more responsibility for the content which appears on their sites, not just fake news but also hate speech and extremist propaganda.

Second, they must drop the pretence that they are simply platforms and channels for publishers’ rather than media companies themselves. They have fast become the main source of news for significant portions of society. The reality is that they are influencing or even deciding via algorithms what information is consumed.

In this respect, it may be time to re-examine Big Tech’s privileged status under section 230 of the Communications and Decency Act crafted in 1996. This has allowed the tech firms exemption from liability for nearly all kinds of illegal content or actions perpetrated by their users (apart from copyright violations).

As my colleague, Rana Foroohar has written: this amounts to a get-out-of-jail free card allowing Big Tech both to remove or publish content without assuming liability. They are censor and publisher combined. Twenty years on from the original act, it is worth asking the question whether Big Tech should still enjoy that privilege.

In fairness, both the leadership at Facebook and Google appear to have recognised the gravity of the problem. In April, Google announced plans to improve the quality and reliability of its search results, following criticism that showed results for sites denying the Holocaust.

Google is now hiring humans — we used to call them editors — to train the company’s search algorithms to spot low quality and false content. Google users can also report when the Autocomplete feature yields poor results.

Facebook is also deploying a “related articles” feature which appears alongside popular articles, including made-up news articles. This is designed to limit the damage of fake news without entering into outright censorship.

Both Facebook and Google are also in talks with major news publishers to support paid-for content — to my mind, the best way for quality journalism to survive and thrive, barring philanthropy.

Among the measures under consideration are how to flag trusted sources to users (though trust, as with beauty, is usually in the eyes of the beholder).

But the uncomfortable fact remains that paid-for content is penalised under Google’s search algorithms which prioritise free content, perforate pay walls and champion scale — though there are signs that Google is re-examining the terms of engagement of “first click free”.

Similarly, Facebook favours free content through the terms and formats of its content such as Instant Articles, while the branding of publishers’ stories on both sites makes it hard for readers to distinguish between trusted titles and fake news.

My firm belief is that it is time to level the playing field between Big Tech and the real news business.

Ladies and gentlemen, we may not have entered the post-factual era — that is a matter to be debated and determined by philosophers. But we are dealing with the serious threat of fake news.

This is a phenomenon which present a challenge to the business of serious journalism.

We who pursue that business must rededicate ourselves to an old task: that of aggregating and verifying sources.

We must go beyond providing the first intimation of significant events, the first analysis of those events; the first commentary on their meaning.

We must endeavour to put the imprimatur on those sources, assessing them for reliability, quality and context before passing them on to readers.

At the FT, we have a cast-iron rule: better to be right than first.

This is vital when opinion too often trumps fact. We need to keep the two separate.

In so doing, I believe we will not only survive and thrive as quality news brands.

We will have won a small victory in our daily battle against falsehood and fake news.

Thank you.