30 years ago in the USA, the parents and grandparents of today’s Twitter trolls and YouTube conspiracy video makers had no choice but to call up their local talk radio station if they wanted a mass audience for their hateful and/or mad views. And while the talkback radio genre is still going strong today, in the USA and elsewhere, it shocks people less often. It’s normal. But in this 30th-anniversary production of Eric Bogosian’s Talk Radio we get a 1980s view of this then burgeoning form of media, and it’s still as disturbing as it was then.

In Talk Radio we see what happens behind the scenes and on air during one edition of KTLK’s Night Talk with Barry Champlain. Barry (Matthew Jure), an angry chain smoker with little patience, is taking calls from the usual role call of eccentric regulars, single-issue campaigners and crazies, while producers Stu (George Turvey) and Linda (Molly McNerney) make sure there’s always someone on the line. But then station manager Dan (Andy Secombe) arrives to inform the trio that the executive team from Metroscan, who own 375 radio stations, are listening in to the show with a view to syndicating it nationwide.

This should be great news, but Barry’s not the type to want to impress the suits. Instead, he provokes them and his audience by breaking the news on air that the show’s about to hit the big time. As Dan turns pale, seeing the deal he thought he had in the bag disappear in front of his eyes, Barry sits back knowing that his callers – who’d love to go national too – will not disappoint when they phone in that evening.

And they don’t. A 16-year-old has just found out she’s pregnant, now she wants the station’s help to track down her boyfriend. Kent (Ceallach Spellman), a teen who’s bunked off school for a couple of days to party with his girlfriend, is worried that his girlfriend won’t wake up. And a neo-Nazi’s worked out that Barry must be Jewish, so he’s sent him a bomb.

This is riveting stuff and the cast play it perfectly, really capturing the atmosphere and tension of a live radio show which isn’t going to plan. You even start to understand the appeal of this sort of programme, albeit as the cracks start to show. Why would Barry be the first person you call when you find out you’re pregnant? Or when your girlfriend won’t wake up? And what qualifies him to dispense views and advice and to tell others to shut up?

Barry seems to wondering this too, and in a moment of daring, desperation or deliberate career suicide – it’s hard to tell – he invites Kent to come into the studio. This makes for a very dispiriting spectacle. Kent is mostly a fame-seeker, with little of substance to share. And so is Barry. And when the lights fade on Barry’s end-of-show sign-off, plunging Max Dorey’s stark parody of an 80s radio studio into darkness, this really feels like the end of it all.