Last summer, the actor and writer Simon Pegg and the writer-director Edgar Wright holed up for a week at Pegg’s home in Hertfordshire to see if they could break ground on a fourth feature film together. Their previous three, aka the Cornetto Trilogy – Shaun of the Dead (2004), Hot Fuzz (2007) and The World’s End (2013) – are all standards on any list of the best British films of the 21st century, and have made both Pegg and Wright bona-fide Hollywood heavyweights. (The pair also created Spaced, one of the all-time great sitcoms, which Pegg wrote and starred in with Jessica Hynes.) But progress on film number four, Pegg admits, wrinkling his nose, was slow.

Was it the pressure of following those previous iconic films? Pegg shakes his head. “Edgar bought his dog, Peter, and Peter was very distracting,” he replies, in his West Country-inflected half-drawl. “I have three dogs; they are schnauzers, too. Well, two now, but I had three then, and they’re quite well-behaved. But Peter’s a little rascal.”

Pegg and Wright did, though, make some decisions last summer and it’s bad news for anyone hoping for a Cornetto quadrilogy. “Whatever Edgar and I do next, we’re not going to rely on what we’ve done before,” says Pegg, whose hair is slicked back, beard neatly trimmed, and is wearing oversized, retro glasses with amber-tinted lenses. “I like the idea of pissing people off. There’s something fun about torching everything. Everything that people think we are, that’s what we won’t be. We should just do something that no one’s expecting.” Pegg laughs, “But no one wants!”

Or at least they don’t realise they want yet. “If I ever do an Instagram Live or whatever, people are always like, ‘I need Shaun of the Dead 2 in my life.’ And I’m like, ‘No, you don’t fucking need Shaun of the Dead 2! The last thing you need is Shaun of the Dead 2! It’s done. Move on!’”

Pegg is sort-of joking, but also sort-of-very-much not. He wrote Spaced and Shaun of the Dead in his late 20s and early 30s because he believed – probably accurately – that the only way to snag the acting roles he wanted in first TV then films was to create those parts himself. He lived in flatshares in north London and had been obsessed since childhood with sci-fi, zombies, video games and action movies, and all these elements found their way into the scripts. Pegg drank a bit too much and had a slightly chaotic life; so did his characters.

But Pegg, these days, is very different. He’s 53 now and lives with his wife, Mo, and their teenage daughter, Tilly, in a house surrounded by fields. He’s teetotal and in confoundingly good nick: Tom Cruise once called him “Eight-Pack Peggles.” Yes, Tom Cruise, he’s a pal, the pair having worked together for more than 15 years on the Mission: Impossible series, the seventh installment of which, Dead Reckoning, Part One, is the reason we are here today. Pegg knows he no longer has to write parts to be asked – often by his boyhood heroes – to act in them: he’s been Scotty in three Star Trek films, appeared in 2015’s Star Wars: The Force Awakens and Steven Spielberg cast him as one of the Thompson Twins in The Adventures of Tintin.

“I say no to a lot of things,” says Pegg, in the garden of a grand house in Hertfordshire (not his) that is the backdrop for the photographs on these pages. “I made a name for myself as a comedic actor, but I’d quite like to flex different muscles. And I didn’t plan to be a comedic actor. Comedy was just something I enjoyed and seemed to be able to do. Now if I get offered comedies I turn them down, because I want to do it with Edgar and nobody else.”

The changes have been more profound than film choices. Pegg has come to look at nostalgia as almost “a neurological disorder” that makes us resistant to change. “This culture of infantilised adulthood, all these grown-ass men arguing about fucking superheroes online, and meanwhile the world is falling apart in so many different ways,” he says. “And that’s why we will all go to hell. Because no one will grow the fuck up any more. Everybody’s so plugged into being a child, you know?”

Back in 2009, he called his autobiography Nerd Do Well. That title doesn’t fit any more. “I’ve aged out of a lot of what people assume I’m about. I don’t feel like I’m that geeky guy any more, particularly. I don’t have the same interests I had when I was 35 or 40 even. I’d much rather watch Succession than some sci-fi.”

Pegg’s ascent remains one of the great, recent Hollywood creation stories. In one of the most entertaining parts of it, he and Wright were asked in an interview, after Shaun of the Dead, whether they planned to leave the UK behind and make action films in the US. Pegg responded, “It’s not like we’re going to go away and do, I don’t know” – scanning his brain for an imaginary, and unimaginable, blockbuster – “Mission: Impossible III.”

The reply was honest. Pegg had not long before done an audition for a small part in the Mission: Impossible franchise, something involving a helicopter, and heard nothing. But then, the original director, Joe Carnahan, left the project and Cruise brought in Alias creator JJ Abrams, who was a huge fan of… Shaun of the Dead! Ricky Gervais was set to play Cruise’s sidekick Benji Dunn, but dropped out and Pegg was given the nod. “So it was a huge irony that I’d said, ‘I’m not going to go off and do this,’” says Pegg. “But then, at that time, there was this attitude that anyone who went off to Hollywood was betraying their roots in some sense or selling out. It’s not like you cross some misty bridge at night and never come home again. So many people assume that I live over there. But, you know, I live in Hertfordshire.”

Pegg’s big-movie break in Mission: Impossible III proved to be intense and unsettling. For the child who had grown up obsessed with film in first Gloucester, then Stratford-upon-Avon – his father was a musician, his mother acted in local theatre; they separated when he was six – it should have felt like everything falling into place. But Pegg was starting to unravel mentally. He had suffered bouts of depression since he was 18 and his fall-back coping mechanism was to drink heavily. By 2005, when he landed in Los Angeles to start the shoot, he could barely hold it together.

“I was not in a good place, emotionally and physically,” Pegg recalls. “It was a weird thing as well, because the dreams I’d had as a kid were manifesting and I wasn’t happy and I couldn’t figure out why. And that was down to personal things, depression. I had to get happy in myself before I could start enjoying anything else. Which I did. But at that time it was very frustrating to be there and not be able to fully enjoy it, because I just felt all at sea.”

Pegg had been accustomed, on the projects he wrote, to working every day. Now, on Mission: Impossible III, he had to be always available, but was little used. “I was put in a hotel in Beverly Hills and I waited for eight days before anyone called me and told me what I was doing or gave me any lines,” he says. “I went completely stir crazy and I was drinking to pass the time. Then you get hungover and you wind up not feeling great. I didn’t have a car. And I remember the hotel had a car service and I got them take me down to the coast, to Santa Monica and I sat in Ye Olde King’s Head, this British pub, and drank Stellas to feel some semblance of normality.”

It would be a few more years before Pegg sought help and went to rehab: rock bottom came in July 2011 after a chaotic four days at the Comic-Con convention in San Diego, California. He insists he can see the effects of the drinking in his performances around this time, but nevertheless, Benji Dunn became a key character in Mission: Impossible, an irreverent comic foil to Cruise’s intense Ethan Hunt. With each film, Pegg was given more to do and, perhaps not coincidentally, the franchise has not only not tailed off, but ramped up the action and the jeopardy with each installment.

Part of the thrill, undeniably, is the vicarious pleasure of watching the world’s most famous movie star engage in high-stakes lunacy. The Mission: Impossible films tend to use real locations – rather than green screen or soundstages – and Cruise does the stunts without camera trickery. These have included scaling the half-mile-high Burj Khalifa tower in Dubai without a harness in 2011’s Ghost Protocol, and clinging on to the outside of an aeroplane as it took off in Rogue Nation (2015). In Dead Reckoning, Part One, we can see from the trailer that Cruise careens off a cliff on a motorcycle. “This is far and away the most dangerous thing I’ve attempted,” Cruise has said.

Pegg, who was on location in Norway that day, agrees. “I’ve only ever seen him nervous a few times: one, when he was hanging off the plane in Rogue Nation and this time,” he says. “And yeah, he did it, I think, six times in one day. And we were up there when he did it. And it was scary, because we’d see him go off and he’d disappear and we’d just wait and then there would be silence until we heard the canopy and we’d know the chute had opened.”

Off-screen, Pegg and Cruise have become genuine friends. They don’t talk about religion – Cruise is a Scientologist, Pegg an atheist – and it hasn’t stopped being weird, at least for Pegg, that they might jump in a helicopter one afternoon, for example, and go swimming with sharks off the coast of South Africa. But the admiration is obvious. “What you get with the Mission films is the presence of true danger,” says Pegg. “It delivers an authenticity, which I think is absent from almost every other action franchise, because not only are those stunts being done, they’re being done by him.

“It’s like Buster Keaton, when the house front falls down and he goes through the window,” Pegg continues. “That’s still more exciting to look at than 1,000 CGI aliens coming at you. And that’s what Tom really understands. He understands film. He understands the audience. He probably knows more about filmmaking than anyone in the business. He’s been around longer than anyone that’s in power at a studio. He’s the real deal.”

Pegg remains highly ambitious for his career, but he does admit that, otherwise, he finds it harder to leave home these days. He has a cinema room and he’s working through a list of the 100 best horror movies with his daughter, Tilly. “Everything from Killer Klowns from Outer Space to Hereditary and The Human Centipede.” Erm, how old is she? Pegg smiles, “She’s just about to turn 14, but she loves it. She really loved The Shining. She’s very interested in the actual filmmaking process, and performing as well, so I feel like she’ll probably drift into the family business in some capacity.

“I love, love, love my home life,” Pegg goes on. “And it’s what I want to maintain through my job. If I can keep that, I’ll be happy. I never want to leave the house, really. I don’t go to parties. I don’t like going out. I’ll avoid having to go anywhere if I possibly can. The happiest place for me is in my armchair watching TV with my dogs and my daughter.”

One event that does get Pegg out of the house is a Coldplay gig. He met the band in the late 1990s, and became close with Chris Martin. They would go to the pub and then come home and Martin would sit in the kitchen playing acoustic guitar. At the V Festival 2001, Martin asked Pegg if he wanted to come onstage and play the harmonica and it’s become a rolling invitation over the years. Last summer, Pegg joined the band on tambourine at Wembley Stadium for their song A Sky Full of Stars. About a minute in, Martin stopped the music. After apologising to the 90,000 crowd, he introduced Pegg as “the world’s number one tambourine player” and said, “He’s our brother, and we love him so much.”

“With the harmonica, you’re always worried you’re going to hit a bum note,” says Pegg. “But it’s such a low-pressure gig. They handed me the tambourine on a cushion. It was so much fun. He’s such a sweet… they are four very, very cool guys. And I’ve seen them go from indie darlings to stadium fillers, and they’ve not really changed at all as people.”

For Pegg, that’s a high compliment. He certainly has changed over the years, but he hopes that his “core fundamental personality” has been unaltered by the unexpected ride he’s been on. “Fame doesn’t necessarily turn you into an arsehole, but it brings out the arsehole you’ve always been,” says Pegg. “I think you have to be smart to be famous. Because you have to constantly understand that it doesn’t really mean anything.”

Does Pegg think he’s managed that: not being an arsehole? “Well, I hope so,” he says, with a grin. “You tell me!”

Mission: Impossible – Dead Reckoning, Part One is in cinemas from 14 July

Stylist Vivian Nwonka; photographer’s assistant Bertie Oakes; grooming by Tara Hickman using 111Skin; locations by lordshippark.com