When I look at the dwindling circulation graphs for Britain’s newspapers the image of a glider plane comes to mind. It’s being piloted expertly – for many remain products of high quality – but decidedly to earth.

I am also reminded of a ride I once took on a milk float driven around Blackburn by John “Jimmy” Mather. That had been his family’s trade for a generation and all was well until Blackburn changed and a large number of families of Asian descent moved to his patch. Many, especially the women, had no English. He couldn’t speak to them, he couldn’t sell to them. He could have thrown up his hands and piloted his own sales graph to decline. Instead, he learned Gujarati. Not fluently, but enough to connect with and befriend his customers. The market changed, so Jimmy changed. There is a great deal our press could learn from Jimmy.

We have a 20th-century press ill-equipped in spirit and practical capability to connect with the diversity of 21st-century Britain. Newsrooms are struggling to break free of the thinking, hiring and deployment practices that may have served them well over the decades but require urgent revision if they, like Jimmy the milkman, are to connect with the potential customer base as it is.

And it’s worse than that. Our newsrooms aren’t where they need to be in terms of any of the strands of diversity – gender, disability, sexuality, race, religion. Over the 30 years I have worked in national newsrooms, they have also become less diverse in terms of class. We have had, in our past, editors who entered the newsroom as copy boys, transporting paper ripped from typewriters around the office. That cadre and those accessible points of entry have been filtered out. In recent years, it has been the degree as standard for recruits, preferably one from the Russell group or Oxbridge.

But what the industry has also manifestly failed to get to grips with is visible diversity. Last year the Reuters Institute for the Study of Journalism revealed that94% of British journalists were white and 86% university educated. Compare that with what we know of our country from the 2011 census: of 56 million residents in England and Wales 86% were white, 8% were Asian or Asian British and 3% were black African, black Caribbean or black British.

Does that matter? In Press for Diversity, a documentary I’ve made for BBC Radio 4, I argue that it does, not just in moral terms – that a press purporting to cover a diverse nation, and a diverse world, should itself be diverse – but also in terms of the glider’s sorry trajectory. A non-diverse press cannot understand or easily connect with a diverse population and potential readership.

Imagine a Tesco catering to a diverse area that didn’t stock its shelves with products to match. Within weeks of Polish migrants arriving in my part of east London, the supermarket shelves began filling with Polish sausage, breads, beers and beetroot. Industries that compete and thrive have antennae that tell them when the market changes and wills them to adapt. Either we have had faulty antennae, or we have lacked the will to fully respond. That has obvious and tangible results.

One is that the breadth of stories we cover is limited. The bubble that preoccupies us encompassing Westminster, London and the south-east is small enough, but then we limit it further by restricting our ability to discover, understand and cover the joys and pains, issues and concerns, rows and celebrations that punctuate life in minority communities.

 There is a defensive view that says diversity doesn’t truly matter in that regard. A story is a story is a story and a good journalist – of whatever background – can get it. There’s some validity to that. But what are the chances of a white British journalist picking up early on, say, a spate of jewellery robberies on well-to-do Asian families in the suburbs – unless they are tipped off by the police? Or on what black churches are doing to compensate for cuts in council services to elderly people? Sathnam Sanghera of the Times told me of his reporting on the views of Indian families in Wolverhampton over Brexit. They felt comfortable with him and the process gained from that.

Then there is the prioritisation process, the decisions we make about what matters. That too benefits from diversity and can otherwise be skewed. Charlie Brinkhurst-Cuff, a journalist of mixed heritage, recalls one editor’s excitement about news that a girl was missing. “He shouted: ‘She’s white, she’s middle class, she’s pretty, we need to get on this’.”

And what of accuracy? We are all taught to check and check again. But how much is that process assisted by the store of background knowledge we carry that tells us what seems feasible or that an element of a story as told doesn’t add up. Miqdaad Versi, of the Muslim Council of Britain, says the media’s lack of knowledge – and perhaps of care – results in the publication of stories about British Muslims that are often overheated and frequently wrong. Assiduous in flagging them up, he has secured more than 30 corrections already this year. Think hard on that: why would anyone buy a product that regularly misrepresents them?

What we see from the inside as mistaken or sloppy presents from the outside as malicious. I recall standing outside the home of Mark Duggan, the young black man shot by police whose death led to the 2011 riots, as a minister urged loved ones to stretch their hands towards his coffin and say goodbye. The accounts in the Express and Mail Online suggest their reporters did not hear the minister. The Mail headline said: “Gangsta Salute for A Fallen Soldier”. The Express said: “Gang culture was all too visible again on the streets of London.” Who of those present would rely on those publications again?

The penny is dropping. Many media groups – Associated Newspapers, Sky, Reuters, Bloomberg, the Press Association and the Financial Times – sponsor the Journalism Diversity Fund. Others have their own schemes to attract a broader mix of entrants. Among the initiatives at the Guardian are Scott Trust bursaries and a long-running positive action scheme. The Evening Standard is also being proactive with its own apprenticeships programme – hoping to broaden its pool of journalists by class and race. Rupert Murdoch’s News UK, which invited 21 students to a summer school during the holidays, is also seeking talented apprentices.

But how much are we willing to change? I debated this point with Neil Wallis, a former editor of the People and ex-deputy editor of the Sun and the News of the World. We agreed on the need for diversity. But while he said all that was needed was to make opportunities available, I argued that if a diverse workforce was essential rather than desirable, the press needed to create it, proactively seeking out talent if need be.

His fear was quotas and anything that smacked of affirmative action. I understand that. Only the best, of whatever background, should make it to national newsrooms. But surely – if we conclude that diversity is important, both morally and commercially – we can seek out or mould the best; deploying the skill and ingenuity for which British journalism is famous. It’s no more daunting than an old milkman learning Gujarati.