Never before has a radio soap crossed so far over from fiction and into the real world. Never before has it become imperative to listen to each and every episode of The Archers (just after 7 p.m. on Radio 4, every day except Saturday) as if by being there, listening in on the ether, we can in some way stand alongside Helen Titchener and defend her from her poisonous husband Rob as he tries to entangle her further in his stifling, controlling web. Some listeners have been so appalled by the current storyline, horrified by the insidious way Rob is trying to take control of his wife, that almost £60,000 has so far been raised in a real live charity appeal on the internet. Just look for ‘The Helen Titchener Rescue Fund’ on JustGiving.

Unfortunately no such relief will actually reach Helen; the charity Refuge, for victims of domestic abuse, to which the money will go, has not made it into fictional Borsetshire. We can only sit by and listen as Rob slowly squashes the spirit out of Helen, wondering at her failure to recognise what is happening, and desperate to reach into the radio and save her.

But why do we care so much? Why go to the length of setting up a rescue fund? After all, Helen does not actually exist, nor Rob. No one will really get hurt as this storyline unfolds. She’s the mere victim of capricious scriptwriters in search of a hook that will keep listeners tuned in day after day to the Radio 4 soap. The only man guilty of torturing Helen is Sean O’Connor, the soap’s editor, who has form on using domestic violence as an audience draw: his previous work experience was on EastEnders. Yet such is Helen’s plight that listeners are taking to extreme measures in her defence. Fans of the soap are out in force on Twitter and other social media every evening, lambasting Rob as a scoundrel and calling for an end to Helen’s protracted torture. (It has become impossible for Timothy Watson, the actor playing Rob, to appear at Archers events, so vitriolic is the abuse thrown at him by disturbed listeners.)

Helen, for those of you not addicted to The Archers, is the 36-year-old daughter of Pat and Tony Archer, organic farmers in Ambridge. She had a troubled past, suffered from anorexia, had a boyfriend who committed suicide, decided to have a baby by IVF while still single, then fell victim to the dastardly charms of cattleman Rob Titchener. He whisked her off her feet with his gentlemanly ways before she discovered that he was already married, which he just brushed aside, declaring his estranged wife to be ‘a witch’.

As soon as the divorce came through, he rushed Helen away to be wed before she had the chance to tell anyone. Then, in a controversial episode, he more or less forced himself upon her after getting her squiffy on champagne, so that she would fall pregnant with ‘his’ child. He is now so overprotective of her that she has stopped work, stopped driving, stopped seeing anyone except him and her son Henry.

Weirdly, Helen’s mother Pat, a dyed-in-the-wool, Greenham Common-supporting feminist from the 1970s, has not seen through him, and the net is closing in on Helen. Recent episodes have given us Rob talking to little Henry and trying to turn him into an agent against his mother, an undercurrent so sinister it’s hard not to wince, physically repelled by what’s being said and done on air.

Helen, it should be said, is no pushover as a character, in spite of her emotional vulnerability. She has had her own career (making prizewinning cheeses), and has plenty of friends and family to provide emotional support. She had no need of a husband to provide for her financially, or for Henry, until Rob came along. Is this what provoked him? Knowing that Helen had less need of him than he of her?

Lately he’s called in his mother for back-up in his campaign of intimidation, inviting her to stay, ostensibly to help Helen look after Henry over half-term, in reality to keep an eye on her. Helen has so far not stood up against any of this. But for how much longer? Meanwhile listeners to The Archers are reeling. The Radio 4 soap appears to have blundered into a minefield, and is blowing to smithereens our comfortable notions about marriage in Middle England. The storyline has been so well-written that the situation is utterly believable. We’re left wondering how many women are there out in the shires living day by day with the kind of insidious, controlling, jealous possessiveness exhibited by Rob.

It’s discomfiting because some of the details, some of the lines, remind us of behaviour we’ve observed, husbands who love to be in charge and hate their wives to have opinions and lives of their own. But is there more of this going on now than 45 years ago, when Refuge was set up? Or is the impact of this particular storyline telling us more about the enduring appeal and relevance of long-form radio drama? Soaps like The Archers allow stories to unfold slowly, giving them depth and conviction. On radio, too, the daily, incremental doses of Rob’s venom work on us with surprising force.

Some relief to those of us who are finding Helen’s plight too disturbing might be forthcoming: O’Connor has just announced he is leaving the radio soap and returning to EastEnders. Too late for Helen’s marriage, which surely must end in some kind of catastrophe (I hope and pray it befalls Rob, not her). Meanwhile, each night at just after seven the theme-tune echoes through the house, Rob’s horrid clipped voice penetrates the room, insinuating thoughts, suggesting ideas, awakening long-buried fears.