Trust is what we who earn our living from the media depend on, and any decline in trust is a cause for concern. The latest data from the Reuters Digital News Report shows a decline in trust in the UK media of 7%. In one YouGov survey, Wikipedia was held to be marginally more trustworthy than the BBC. So what’s the problem and what can be done about it?

It is due, I believe, to two main factors: the increased polarisation of our society and the increased use – particularly by the most committed and most partisan – of social media and alternatives to what they call the MSM, the mainstream media. “We’ve moved to a marketplace where quality journalism competes on an equal footing with raucous opinion,” explains Richard Gingras, head of Google News. He goes on to point out the key challenge posed by social media: “Affirmation is more satisfying than information.”

In the space of just three years, we have seen a referendum on whether to split up the UK, followed by one on whether to split away from the EU. We have had two general elections, changed prime ministers, gone from having a majority government to a minority one propped up the DUP, and seen the unlikely rise of an opposition leader who was at first regarded by himself, never mind anyone else, as having no chance of getting to 10 Downing Street.

Those who see themselves as fighting the establishment – for example, Scottish Nationalists or Ukip-ers, Corbynites or Greens, backers of leave pre-referendum but, since the vote, backers of remain – have not just complained about the MSM. They have established their own alternative media sites – Wings over Scotland, Westmonster, the Canary, the Skwawkbox, Novara Media and Evolve Politics – or, in the case of pro-EU supporters, a new newspaper, the New European.

They would all be horrified to be compared with one another, since what motivates them is the belief that the other lot are not just mistaken but an existential threat to the future of their country, but they often respond in similar ways. Their most shared and liked stories are attacks on the MSM and the BBC in particular. They share a certainty – fuelled by living in a social media bubble – that we reporters and presenters are at best craven, obeying some diktat from our bosses or the government, or at worst nakedly biased.

Our critics now see their attacks as a key part of their political strategy

Some might say “it was ever thus”. Ever since Winston Churchill accused the BBC of being unwilling to choose between the fire and the fireman in the General Strike, broadcasters have faced criticism. But this time it is different. First, because the fracturing of our politics means the criticism is coming from all sides and from grassroots campaigns, rather than from whichever of the government or opposition feels most vulnerable. Second, because in the past the purpose of the attacks was to persuade or bully the BBC or, occasionally, ITN into changing the way it reported a particular story or to drop this or that programme or journalist.

Our critics now see their attacks as a key part of their political strategy. In order to succeed they need to convince people not to believe “the news”.

Campaigners on left and right have been looking at and learning from the method behind what some regard as the madness of Donald Trump’s attacks on the “failing” press as purveyors of “fake news”. Italy’s leftwing populist Beppe Grillo has described the Italian media as “the opium of the people – they hide the truth to reassure you, while you slowly die”. In Germany the rightwing Alternative für Deutschland party (AfD) has revived the Nazi insult “lugenpresse”, meaning “lying press”.

Attacks on the media are no longer a lazy clapline delivered to a party conference to raise the morale of the party faithful. They are part of a guerrilla war being fought on social media, hour after hour, day after day. I believe the BBC should respond by adopting a mission to engage with those who do not treat news bulletins as “appointments to view”; those who don’t trust what they’re told; and those who crave the tools to separate what is true and what is important from the torrent of half-facts and opinion, prejudice and propaganda, which risks overwhelming us all.

Steve Hewlett is my inspiration here. We met on Brass Tacks, a BBC current affairs programme based in Manchester. In Manchester, note. I was from the area. He’d been a student there. We … it … had a different perspective from people at TV Centre. Our team included a former merchant seaman with a broad scouse accent and arms covered in tattoos. I have worked with few like him in TV since. The Steve Hewlett Scholarship should be just a first step to finding more like him.

While at Channel 4, Steve worked on a series called Diverse Reports. In his own words, “There was a clearly defined purpose. Wherever you can find the liberal consensus, probe it, probe it, probe it. And if there’s another way of looking at it, broadcast it.” And broadcast it he did, once making a show that examined the case for restoring capital punishment.

We should do exactly what Steve proposed: ask questions – and share online items that ask questions – that all too often are not asked. Again and again over the years, views that start off being seen as extreme quickly become the new conventional wisdom – monetarism, green politics, gay rights, calls for curbs on immigration. Jeremy Corbyn is the political embodiment of the fact that the conventional wisdom is there to be proved wrong.

When I wrote a book a few years ago called Live from Downing Street, the theme that emerged was not bias – to this party or that, to right or left – but the slowness to challenge the conventional wisdom of the day. Most shockingly, Churchill’s pre-war warnings about the dangers of German rearmament were heard by radio listeners not in his own country but in the US. The BBC, influenced by the government, muzzled him.

The way Churchill was handled is a powerful warning of the dangers of the BBC believing it is being balanced by silencing the voices of those who do not represent conventional wisdom. It is an answer to all those who complained that Nick Griffin – who is, let me stress, no modern-day Churchill – should never have been invited on to Question Time. It’s a riposte to Brexiters who fill my timeline with demands that we should not interview “that failed leader” Nick Clegg, to remainers who say the same about Nigel Farage, and to those who argue Nigel Lawson should never be interviewed about climate change. They should be challenged and if, as Lawson did on Today recently, they get their facts wrong we should say so. But they should not be silenced.

Research shows that people who don’t trust the media often think they don’t hear the views of “people like me”. They should, but we should also confidently tell them that they will hear people with whom they’ll disagree. As I once tweeted in response to a complaint from former culture secretary John Whittingdale, “Do not adjust your set. Normal service from the BBC means you will hear people you disagree with saying things you don’t like (that’s our job).”

• Nick Robinson is a presenter on Radio 4’s Today programme, and is delivering the first Steve Hewlett memorial lecture on Thursday 28 September. Donations to Hewlett scholarships can be made at rts.org.uk/stevehewlettfund