Playwright James Graham has said the television industry should start treating class in the same way it deals with other personal characteristics such as race or sexuality.

Citing a report that found only 8% of people in the British film and TV industry are from working-class backgrounds, Graham warned that programme makers are losing touch with viewers.

The creator of Sherwood and Dear England said being working class in Britain is not just about individuals’ income or the jobs of their parents. Instead, it is “a culture, similar to that of growing up in a particular faith or nationality”.

Despite this, Graham said class background is rarely mentioned when it comes to diversity data about who is employed in the television industry as well as which writers have their shows commissioned.

Graham, 42, said he benefited from watching working-class TV dramas with his family in the 1980s and 90s but he fears this experience could be lost.

“If you see a person, or a character, who looks like you or sounds like you on screen, whose experience or dilemmas, or joy, reflects your own … you feel more seen,” he said. “There is a catharsis there, for audiences. A validation.”

The playwright made the comments in his MacTaggart lecture at the Edinburgh television festival. The lecture is seen as an annual assessment of the state of the British television industry and is delivered by a different notable figure every year.

Graham’s show Sherwood, set in the same Nottinghamshire mining villages where he grew up, is returning to screens at the bank holiday weekend.

He thanked the BBC for agreeing to broadcast episodes of Sherwood on a week-by-week basis, rather than release the whole series at once on iPlayer, because this will allow it to be “a collective experience, not just an atomised, lonely, private one”, with weekly national conversations about the topics covered in the show such as levelling up, spy cops, trade unions and industrial strikes.

One issue harming working-class representation in television is the precarious and low-paid nature of much of the work. The industry has been hit hard by a recent downturn in the advertising industry, along with streaming companies pulling back from big-budget shows after years of oversupply during the “peak TV” era of the late 2010s.

Graham accepted that class is hard to measure and “simpler-to-define areas of diversity” such as racial representation can “fire up the activist in us”.

He said another issue is that Britons enjoy sniping at successful working-class people: “It is not just about money. You do not stop being it, the second you get a pay raise. Nor would I offer – and I’m sorry if this sounds exclusionary, or gate-keepery – do you become it, the instant you might drop below a certain level.”

Graham said a key part of the solution is shoring up the finances of the public service broadcasters – the BBC, ITV, Channel 4, Channel 5 and S4C – which invest in shows that Netflix would not touch: “They are the state school equivalent – the equalising force; the subsidised National Theatre equivalent of being given public funding, to relieve some of the commercial pressures, in order to take non-commercial decisions, in finding and training and amplifying voices that on paper may not have an easy, wide audience yet – but one day will.”

He said American colleagues are baffled by the “complacency” in the UK over the financial future of its public service broadcasters: “They wish they had a BBC. We will miss them, if they ever go.”

He also said classic British TV drama and documentaries should be built into a new national curriculum alongside Shakespeare’s plays.

He said there is a risk that children hooked on short TikTok clips become unable to consume an hour-long drama with complicated narratives.

“Being able to concentrate on one thing, in this distraction economy, might be a skill young people lose,” he said.