No one can be in any doubt, after the referendum campaign, that large parts of the British print media have abandoned any attempt at balance. A detailed study by academics at Loughborough University has described in detail how much of the tabloid press ran a relentlessly negative campaign against the EU, but more especially against migrants. While this was balanced, to some extent, by more positive coverage in the Financial Times, Guardian, and Daily Mirror, when weighted by newspaper readership the message reaching the British public was overwhelmingly hostile. Worse, much of the coverage was seriously misleading, not only reflecting the many comments now withdrawn by those supporting the Leave campaign, such as the notorious £350 million a week for the NHS, but also stories vilifying migrants subsequently shown to be entirely false. Indeed, the flow of nonsensical and untrue stories is so great that the EU has had to create a Euromyths website to counter them. Even when forced to retract a story about migrants wrongly described as coming “from Europe,” the editor of Mail Online qualified this by saying “At the end of the day the people in that van did come from somewhere via somewhere. They may not have been from Europe but they were in the back of a van illegally.”

It can, of course, be argued that these newspapers are reflecting the views of some of their readers. In 2015 a satirist posted quotes from Mein Kampf and other Nazi literature on Mail Online’s website, substituting the word “migrants” for “Jews,” leading hundreds of readers to “like” the comments.

But do newspapers matter? In a recent Eurobarometer study, 73% of people from the UK reported not trusting the printed press, the highest level of distrust in the EU and 23% higher than the average. Yet there are reasons to believe they are important. First, the stories that they cover set the agenda for the broadcast media, including the BBC, which still is trusted. And, second, it affects how people vote. We found that The Sun’s shift in support from the Conservatives to Labour in 1997 delivered an estimated half a million votes, even though attitudes to key issues did not change in the population.

But other parts of the media strive scrupulously to be fair. Throughout the referendum campaign, the BBC ensured that both sides of the argument were heard. This is nothing less than one might expect from a public broadcaster. Except, it overlooks one key issue, the concept known as fairness bias. This assumes, implicitly, that claims cannot be objectively verified and everything is a matter of opinion. Thus, just before the referendum the BBC’s political editor described the facts as “elusive,” even though they were easy to find with a few clicks on Google. Crucially, this approach places the views of people who, by virtue of their long years of studying an issue and familiarity with it, on a par with those who have only thought about it perhaps a few hours earlier. As the prominent Leave campaigner Michael Gove summed it up, “people in this country have had enough of experts.”

Perhaps the best description of fairness bias comes from the American creator of the West Wing series, Aaron Sorkin, who put it as follows: ‘ If the entire House Republican caucus were to walk onto the floor one day and say “The Earth is flat,” the headline on The New York Times the next day would read “Democrats and Republicans Can’t Agree on Shape of Earth.”

It is, of course, important that all sides of an argument are heard. It is also important that the values of those who might be considered an educated elite are challenged. However, where the contrary argument is simply implausible or demonstrably untrue, such debate serves simply to confuse.

There were many examples of this during the referendum campaign. One after another, groups with a wealth of experience lined up to argue the case for Remain. The list is almost endless. Thirteen Nobel laureates. Over 60 former presidents of the Medical Royal Colleges. The Royal College of Physicians. As The BMJ noted, they could find no prominent medical or health organisation that supported Brexit. And it wasn’t just health. Even the Society of Motor Manufacturers and the Football Premier League  supported Remain! And in each case the news was greeted with the same refrain. VoteLeave disagreed. Sometimes they went further, where those involved had ever received funding from the EU, this was qualified by accusing them of being hopelessly tainted by having done so. But almost never did they make a reasoned challenge based on verifiable facts and, as been demonstrated clearly, many of the facts that they did use have been false.

Fairness bias does, however, have much broader implications, and especially for those communicating health messages. In 1987 Peter Duesberg attracted widespread attention when he denied the link between HIV and AIDS. This, and other examples, have led to recognition of the role played by denialism in science. At the time this was presented as a genuine debate, with tragic consequences, especially in South Africa. But nowhere is this more apparent in the debate about man-made climate change, an issue about which there is overwhelming consensus in the scientific community, as noted in a critical report by Professor Steve Jones for the BBC Trust. Yet the broadcast media continue to counter evidence from scientists with views of individuals like Lord Lawson, which the BBC justified as “designed to help listeners judge how to assess the recent bad weather in the context of climate change.”

Researchers have much to learn from the referendum campaign. Evidence and understanding of the issues are clearly not enough in what is being described as a “post-fact society” where the “the very idea of objective reality is under attack.” This is a profound challenge to the very idea of science. The research community needs to come up with a response, and quickly.

Martin McKee is professor of European Public Health at the London School of Hygiene and Tropical Medicine.