Was Margaret Campbell, the Duchess of Argyll, really a “a completely promiscuous woman whose sexual appetite could only be satisfied with a number of men”?

The screenwriter Sarah Phelps  has made Margaret, Duchess of Argyll, the heroine of A Very British Scandal, a new BBC drama starring Claire Foy and Paul Bettany as the aristocrats whose divorce transfixed a nation in 1963.

Thanks to Lord Wheatley, who was the only Catholic on the Scottish Bench at the time, the vile behaviour of the duke, a series of photographs showing the duchess performing fellatio on an unidentified man and her own altruistic, if high-handed, refusal to defend herself, the sexual ins and outs of this separation are a matter of incredibly detailed historical record.

“It was,” says Phelps, “all about, ‘Who’s the man?’, ‘Who’s the headless man in the photos?’, ‘How many men did she f**k?’, ‘Who was she blowing?’ And I almost thought, ‘I actually don’t give a shit. I want to know about her. I want to know who she was.’ So the blowjob matters to me in one way. But it matters less in the prurient sense of needing to know who was on the other end of that erection.”

The duchess of Argyll’s attitude to the sanctity of marriage was what moderns would call ‘enlightened’ but which in plain language was wholly immoral

To unpack this all a bit: Ian Douglas Campbell, the 11th duke of Argyll, accused his wife of infidelity and produced a list of 88 men. Some were gay and had never been involved with Margaret, but she chose not to challenge the account, as homosexuality was still a crime and it would have implicated her friends.

Lord Wheatley concluded that she was a “completely promiscuous woman … Her attitude to the sanctity of marriage was what moderns would call ‘enlightened’ but which in plain language was wholly immoral.”

The key evidence at the trial, however, was not the list but the so-called headless gentleman in a set of photographs, showing the duchess fellating someone unidentifiable. The drama is “about as explicit as the BBC can be”, Phelps says.

Foy, who plays the duchess, says she felt exposed and exploited as she struggled with filming the sex scenes. “It’s grim – it’s the grimmest thing you can do,” she told BBC Radio 4. “You feel exposed. Everyone can make you try to not feel that way, but it’s unfortunately the reality.”

“But my thing was that I felt very strongly that it had to be in it, but I wanted it to be female. I did not want it be that sort of awful climactic sexual experience you often see on the cinema screen.”

There’s a wonderful scene in which Julia Davis, playing a savagely caustic woman with a collection of hopping golden phalluses and the unwieldy title of Maureen, marchioness of Dufferin and Ava, has just seen some bonobos in the zoo.

Famously, these likeable primates are at it all day long, and Davis’s lip curls in exhilarated disgust as she describes their constant play and foreplay, before she concludes: “And I thought, ‘That’s just like Margaret.’” The duchess replies: “It’s not my fault if you don’t like it and aren’t any good at it. I do like it, and I am extremely good at it.”

Davis, speaking by phone, seems surprised to have made the leap from comedy to drama. “If I was being really honest, part of me thinks, ‘Maybe I’ll be offered some other good work from this.’” Davis recalls regarding the leads as in a different league.

“I felt like I did when I first started out. I was getting all this work suddenly, and I hadn’t been to drama school. I didn’t know really basic things, like when they say, ‘Can you stand on your mark?’ I didn’t know what that meant. And I would keep standing anywhere but that mark.”

In her first marriage Margaret had to give birth to a stillborn child. On its own, that is absolutely heartbreaking. And after that, she had miscarriage after miscarriage 

She was also surprised to be so interested in the story. “It’s rare for me to like something like that,” she explains. “But when I read it, it didn’t feel like some cosy, British period piece. To me, this show doesn’t feel like the Establishment. I think Sarah Phelps has a similar anger, rebel thing to me.”

That’s exactly what distinguishes the drama from everything you could name with a similar focus on the British aristocracy: not that it’s raunchier or more adult in attitude and storytelling than, say, Downton Abbey or The Crown, but that it doesn’t have that fawning love of poshness that can be off-putting.

That fawning poshness was common in Argyll and elsewhere, even in Helensburgh, which is now officially part of Argyll, and Loch Lomondside. Posh names crop up during this story including the famous film actor David Niven, who is said to have had a romance with the Duchess.

Niven served in the same Army regiment as Patrick Telfer Smollett of Cameron House on Loch Lomondside who was a close friend and neighbour of Sir Ivar and Lady Colquhoun of Luss whose estate is contiguous with Argyll.

The Colquhous’ daughter, Iona, married the son and heir of the Duke of Argyll  whose second wife was Margaret, Duchess of Argyll.

The millionaire novelist AJ Cronin, who was born in Cardross, brought up in Round Riding Road in Dumbarton and educated at Dumbarton Academy and St Aloysius College in Glasgow rented a farmhouse on the vast Argyll estate where he wrote best-sellers, which included Hatter’s Castle, the Green Years, the Citadel and Doctor Finlay’s Casebook.

“I find it really uncomfortable, the level of subservience we have in this country,” Phelps says about Britain. “I find it really strange. We love to serve the big house. We love to know that if we keeled over in our tithe cottage, the squire might come down and give us a farthing. It’s, ‘If I can stand next to this, I’ll be protected. If I’m standing under their umbrella, maybe the rain won’t fall so hard on me.’”

Phelps’s writing implicitly rejects this notion, that the leisured class has more dramatic momentum and potential than average folk. She traces Margaret back to the child and young woman she was before taking her title, finding “a little girl who’d been brought up highly isolated, to live entirely within the male gaze of her father’s approval”.

She was born not into class but money, and a lot of it. She had a terrible stammer, probably the result of being a left-hander forced to write with her right, and a restless, traffic-stopping beauty. She was rumoured to have had an affair with David Niven when he was 17 and she was 15. “I like to think it’s true,” says Phelps, “but I couldn’t put it in the script because it’s just hearsay.”

Margaret’s first marriage was to Charles Sweeney, a businessman. Lasting 14 years, this union has in previous histories been consigned to a footnote in Margaret’s life, Sweeney himself being neither as rich as her father nor as famous as many of her other lovers. But Phelps places this marriage, or at least the events of it, at the centre of her character’s story.

“She had to give birth to a stillborn child. On its own, that is absolutely heartbreaking. And after that, she had miscarriage after miscarriage after miscarriage after miscarriage – having her own two children nearly damn killed her. It’s to the point where it doesn’t matter how much money you’ve got. It doesn’t matter whether or not that mink stole you threw so casually round your shoulders was the most photographed mink stole that day.”

So even though the script takes the contemporary perception of Margaret of Argyll, up to a point – “she was boastful, she was vain, she wanted to be the cynosure of all eyes” – this portrait represents a fundamental revisionism. The duchess was reviled at the time, and is periodically reclaimed as a feminist icon for her sex-positivity and as a proto-LGBTQ+ ally. But she would never have described herself as a feminist. “I’m not convinced she really liked women that much,” says Phelps, “because what could a woman give her? Not what she craved, which was adulation, sex, jewels, validity.”

This is a drama that comes from the same stable as EastEnders’ golden-era storylines

Part of what makes this drama so gripping is the detective work that’s gone in, not to sift truth from fiction in this mightily unusual divorce trial, but in finding a breathing, believable human under the layers of frivolity and scandal that history lacquered on.

A Very British Scandal is fascinated by class and its effects, while being repelled by notions of superiority and servility, yet it is never so revolted that it’s not trying to figure out what’s going on with the people locked within it. Which is an attitude that’s always been discernible in Phelps’s work, since she dropped out of school, left home at 16, began looking after horses and made this discovery: “Never mind cocaine as God’s way of telling you you’ve got too much money – polo is a different league.”

A Very British Scandal is the latest piece of Phelps’s work in a career spurred by indignation at polo players in Bentleys calling for the army “to be sent out against the striking miners” – causing her to end up at Cambridge as a 23-year-old mature student. Eventually, in 2002, she wrote the first of what would be 94 EastEnders scripts.

This is a drama, therefore, that comes from the same stable as EastEnders’ golden-era storylines – the apex of the Slater sisters’ story arc, the time when everyone said it might be as good as Corrie. It follows Phelps’s adaptations of Agatha Christie (five in total – and I loved And Then There Were None) and Dickens (Oliver Twist in 2007, Great Expectations four years later).

These are works that had been rendered on screen before, some multiple times, and they may not have warranted revisiting, had it not been for Phelps’s distinctive outlook, part iconoclast, part psychoanalyst. Phelps mines her characters for the rebel inside. With Margaret of Argyll the scandal may feel very British, but the rebel Phelps uncovers is a citizen of everywhere.