They don’t make them like John Stonehouse anymore — a high-flying politician, handsome, forceful-chinned and utterly crazy. In 1988 he died, aged 62, of a heart attack. But he had also apparently drowned in 1974 while swimming off the coast of Miami. He left a pile of clothes on the beach, then moved to Australia, using a fake passport and calling himself Clive Mildoon.

Australian police arrested him thinking he was Lord Lucan, another strong-chinned English nutter on the run, who was suspected of murdering his nanny with a lead pipe wrapped in bandages. Clear so far?

John Preston, author of The Dig and books on the disgraced politician Jeremy Thorpe and the press baron Robert Maxwell, decided not to write a book about Stonehouse. “I don’t particularly want to be typecast as someone who has spent their entire career resurrecting 1970s reprobates,” he says. He has, however, written a three-part screenplay — his first — titled Stonehouse.

Matthew Macfadyen, best known as Tom Wambsgans from Succession, is in the title role. Preston was so thrilled when the actor accepted it that he rewrote the entire first part.

Stonehouse, a Labour M.P. once tapped for party leadership, outside the House of Commons, in London.

He was right to be thrilled. Macfadyen is Stonehouse; his high forehead — he admits to having “acres of head” — brilliantly encapsulates the way the man expressed bewildered innocence while being spectacularly guilty. His dentition, however, needed work. “Stonehouse’s teeth were a bit of a horror show,” Macfadyen says. They struggled to find dentures that didn’t make him look like “a sort of demented vicar”.

The man in full was more complicated, though. “He’s slightly venal but slightly sympathetic,” Macfadyen says. “He was very plausible, certainly at the beginning of his career, in the sense that he was a good MP — very good work in the developing world and Africa — and tipped for the top, I suppose. Also quite dishy and personable, and people liked him being around. But the vanity was the thing that fascinated me most about him.”

Stonehouse was indeed plausible. It was thought that he could be the next Labour leader after Harold Wilson. But the MP was also a serial adulterer. Keeley Hawes, Macfadyen’s wife, plays Mrs Stonehouse. Awkward? “Oh no! It’s sort of lovely,” he says, though admits it’s also “odd” for couples to play opposite each other. “But it was sort of easier than we imagined it would be, partly because we’ve worked together before.”

They struggled to find dentures that didn’t make him look like “a sort of demented vicar.”

They met on the set of Spooks in 2002 and married two years later. They now have two teenage children and a dog, which came along with them when they were filming Stonehouse in the Midlands. “It was kind of a nice holiday together. A working holiday.”

Macfadyen is a mere 48, so he knew nothing of the story. “I thought I did because I think I conflated him with Reggie Perrin a bit,” he says referring to the 1970s sitcom character who faked his death. This raises a question — which also applies to Preston’s Maxwell and Thorpe biographies — who remembers these people now?

“He’s slightly venal but slightly sympathetic.”

Stonehouse “is a kind of forgotten figure”, Preston says. “And when I wrote Thorpe I did a straw poll in my publishers. Literally not one person put their hand up when I asked if they’d heard of him. And I thought, well, you know, there are two ways of looking at this. I might just go out and shoot myself. Or I could think …” Preston says.

“It’s the truth?” Macfadyen suggests.

“Exactly.”

And in the case of Stonehouse, Macfadyen adds, “You can reintroduce a generation that doesn’t know anything about this to this really rather extraordinary figure.”

Preston presents Stonehouse as a fantasist who could not see that he was heading for disaster. While political ambition blinded Thorpe to the risks of his double life, and money and power blinded Maxwell, Stonehouse was blinded by all three, combined with a staggering lack of judgment. Adultery and vanity were what finished him.

It is said that as minister of aviation he was caught in a honey trap while on a trip behind the Iron Curtain. Czech intelligence provided the blonde, filmed the inevitable and suggested he spy for them, which he eagerly did when he found there was money involved. Luckily for the British he turned out to be what his Czech handler described as the worst spy ever. Macfadyen chortles at this: “I love the way the Czech handler is so offended by how bad he is as a spy. It makes me chuckle. The worst!”

It should be said that Stonehouse denied he was a spy until his death and subsequently his daughter has also denied it. “It never came out as a story at the time,” Preston says. “Thatcher basically decided to sit on it, on the advice of the attorney general. I don’t think there’s any doubt. I mean, there’s a bulging file on him in the Czech secret service archive in Prague.”

Stonehouse dashes toward a waiting car as he leaves Norwich Prison after serving seven years for fraud, 1979.

As Macfadyen notes, there was something almost forgivable about it all. He feels sorry for Stonehouse. He didn’t seem wicked, rather a wildly deluded fantasist. “He had the idea that he was in a film called John Stonehouse, the story of the derring-dos of John Stonehouse — a sort of demented James Bond, the Saint or Edward Fox in The Day of the Jackal. And when he’d come out of prison he would listen constantly to soundtracks of films. There was a whiff of the secret agent about Stonehouse.”

The further almost forgivable truth about him was that he really did love his wife, Barbara. But also he really did love his mistress, Sheila Buckley. He tried to get them to share him but Barbara served divorce papers while he was in prison. After the UK law retrieved him from Australia he was charged with fraud, theft, forgery, conspiracy to defraud, causing a false police investigation and wasting police time. He conducted his own defense and went down for seven years. He married Buckley in 1981.

Keeley Hawes, Macfadyen’s wife, plays Mrs Stonehouse. Awkward?

Preston sees a link between Stonehouse’s double love life and his multiple, invented identities. “It was the weirdest symbolic thing for him to do — he basically hived off one half of his identity. In the same way he wanted to divide himself in two and keep his marriage going, and keep his relationship with Sheila Buckley going, both of which he thought were perfectly reasonable.”

Three’s company … Keeley Hawes as Stonehouse’s wife Barbara Smith, and Emer Heatley as his mistress, Sheila Buckley.

So could it happen again? “It’s very hard to fake your own death these days,” Preston says. “I mean it’s almost impossible. I find it hard to imagine it happening in an era of social media.”

Macfadyen is less sure. “If there wasn’t the Lord Lucan thing he probably would have got away with it.”

Macfadyen and Preston then slip into a game of verbal ping-pong about what Stonehouse actually did after faking his death in Miami. Macfadyen believes he flew back from Australia to Copenhagen to see Buckley.

Preston has a feeling “that he left one pile of clothes on the beach in Miami. Then he went off somewhere and waited for them to be discovered. But then they weren’t discovered, they were just tidied away. So he had to go back and leave a more prominent pile of clothes.”

It sounds comical, but the truth was that Stonehouse did almost get away with it. “He thought — and, in a way, he was right — that he had put on an invisibility cloak and he would get away with it,” Preston says.

On the whole, though, he and Macfadyen agree that, because of social networking and technology in general, it could not now be done.

He really did love his wife. But also, he really did love his mistress.

But there are still fantasists in politics, I point out (Liz Truss among them). “They do lead this tremendously insular life in Westminster,” Preston says. “I think that erodes one’s sense of absurdity, assuming you’ve got one in the first place, which — well, it’s debatable whether Stonehouse did have a sense of absurdity. But no one who had a sense of absurdity could have got himself into that kind of terrible pickle.”

Macfadyen points out that Stonehouse had no idea how ridiculous he made himself by conducting his own defense at the trial, even though it took three months and “drove the judge mad with frustration and boredom”.

So what’s next? The actor is now “about two thirds of the way through” filming series four of Succession. Each season takes about six months to make. “We shot the pilot on election day in 2016, so it has been nicely bookended, the majority of it, by those four years while Trump was in power.”

Meanwhile Preston is writing books he’s not allowed to talk about and a screenplay for “a big conspiracy thriller set in 1750s London” that, weirdly, “is a bit like” Roman Polanski’s Chinatown.

Both men have a busy 2023 ahead then. Personally one of the first things I plan to do this year is a Stonehouse and leave a pile of clothes and a passport on Blackpool beach. Each to his own.

Stonehouse is available to stream in the U.K. on ITVX. It will stream in the U.S. on BritBox beginning January 17

Bryan Appleyard writes for The Sunday Times of London and is the author of 10 books