When Mr Danny Boyle set about recreating one of the greatest vibe shifts of the late 20th century, he wanted it done properly. To tell the story of the Sex Pistols, the young punk band that changed British culture for ever in one potty-mouthed, shouty swoop in 1977, he wanted to keep things as raw as lead singer Mr John Lydon’s vocals. Boyle, director of Trainspotting and 28 Days Later, wanted the gigs in Pistol, his new TV miniseries, to be filmed live, no pre-recording, post-recording or dubbing, to capture what cemented the band’s ramshackle shows in history. The young actor charged with recreating Lydon, who went by the stage name Johnny Rotten, in all his spit-strewn glory had never been a singer, not even karaoke.

“I remember, after I’d been cast, driving home from someone’s house and putting the Sex Pistols on in the car and singing,” says Mr Anson Boon, 22, from Cambridgeshire. “I’m shouting, ruining my voice. I’m thinking, how am I ever going to do this?”

In a bid to get into full-throttle punk mode, he went to bandcamp for three months, which involved learning to stretch his vocal chords an octave higher than his natural singing voice.

“We stretched the muscle, as you might teach someone to do the splits,” Boon says between sips of honey tea and Strepsils, sitting at the bar in a Soho hotel. Singing lessons may seem like a curveball. The Sex Pistols weren’t exactly known for their pitch-perfect renditions. The allure of their gigs was quite the opposite. Everything, singing included, was on a knife edge. They were an angry and loud cultural juggernaut, who changed culture at the same furious pace as their accelerated punk hits, which quickly earned them legendary status.

“I went into it naive,” says Boon, “and very stupidly said, ‘It’s OK I can’t sing because Johnny Rotten can’t sing either’. Boy, can he sing. He’s just unique. It’s just not conventional.”

The young actor stretched himself in other ways for the role, reading all Lydon’s books and guitarist Mr Steve Jones’ memoir, Lonely Boy, which Pistol is based on, and fell in love with the singer as a character. Each morning on set, he would have a cup of tea and look at a piece of paper with 10 keywords on it that people used to describe Lydon and words Lydon has used to describe himself. They were all distinctive adjectives that showcased the roots of Lydon’s cultural significance. He was provocative, an outlier, whose alter ego seemingly revelled in public disdain when a large part of a star’s appeal was to be adored.

Boon starts listing words such as “incandescent”, “lacerating”, “impetuous”. “Anti-star was another good one,” he says. “He was the anti-star.”

Boon’s portrayal of an anti-star may make him a star himself. But taking on a larger-than-life character in Pistol was a challenge his director was all too aware of. “You have to start by admitting it’s impossible to cast John Lydon,” says Boyle. “It’s his contrary instinct to whatever is agreed on, or taken for granted, that makes him so difficult to capture. He would even contradict that.”

Boyle first saw a snapshot of that contrary spirit in Boon’s audition, where he improvised Lydon’s audition for the Sex Pistols. “I knew that was as close as we could dream of coming because it was accurate and felt truthful”, says Boyle. “But there was also something unmanageable in it. Magnetic and repulsive. And funny, too. A wit that came out of the genuinely uncomfortable.”

When the Sex Pistols crash landed onto the British music scene in 1977, they made a lot of people very uncomfortable. In notorious anthems such as “God Save The Queen”, they lampooned the British establishment. They tore up the fashion rule book, quite literally with ripped clothes, safety pins, dyed static hairstyles and S&M-inspired outfits made popular by Dame Vivienne Westwood’s shop, Sex, on the King’s Road in Chelsea. Their gigs were shambolic, anarchic and changed culture.

Their gig on 4 June 1976 at the Lesser Free Trade Hall in Manchester was attended by about 40 people, some of whom went on to form iconic bands including Joy Division, The Fall and The Smiths. The band represented radical change for a generation chomping at the bit for it.

In Pistol, Boon has to embody that change as Johnny Rotten. A young Rotten was like barbed wire. At his most intense, his glare felt powerful enough to rip you open. Boon knew the similarity wasn’t obvious. He looks more like a young Mr David Bowie, which he’s heard before and from those who worked with the man himself.

His dad was the first person who told him it wasn’t an impossible task to transform himself into Rotten. Boon lost weight for the role, tried 14 different wigs and worked with makeup artists to sculpt his face to match Lydon’s bone structure. He got into the habit of pinching his lips.

“He has much smaller lips than me,” says Boon. “So I had to practise…” He demonstrates as he says it. His lips become paper thin and taut, which makes his eyes pop even more intensely. Like a pop-up book, Rotten emerges from Boon’s cherubic face.

Like a loyalty card, Boon kept acquiring Rotten’s traits. He can still turn his legs uncomfortably inwards until they’re pigeon-toed, embodying the spindly bones of his on-screen character. Paying homage to Lydon involved embracing it all, “even the lawsuits”, says Boyle.

Last year, Lydon lost a court case to stop the series using Sex Pistols tracks. Afterwards, he issued a statement that detailed a lack of involvement with the show and alleging he learnt about the proposed use of Sex Pistols music in Pistol “just a few hours” before it was announced. His former bandmates disputed Lydon’s claims.

Boyle, who met Lydon through the Olympic opening ceremony in 2012, which he directed, says, “I did reach out to him in January before we began shooting in March for Pistol, but I sadly couldn’t get past his manager this time.”

I ask Boon what it’s like to do his job with this in the background. “I became such a fan of him and I’m so romantic about what he achieved in those three years as the Sex Pistols and what he went on to do with [his follow-up band] PiL,” he says. “It just fuelled me to chase authenticity all the time and to respect his voice, his version of events. Our story was anchored with Steve’s book. I always wanted to balance that with how John remembers things as well. I just always wanted to do him justice. I would have loved to have met him and, whatever he might say, I just hope he can recognise that everything I did, every choice I made in my performance, was out of pure admiration and respect.”

Did he notice any parallels playing Rotten? “The most significant and perhaps the only true parallel was the same fire burning, about wanting to achieve something,” he says. “He wanted out of his council estate in Finsbury Park and he wanted success. I guess I felt that as well, that ambition and determination.” For Boyle, the parallels were even closer to home. “Anson loves Lydon, in a way even more than I do,” he says. “Like John, he too comes from a tight, loving, working-class family and certain things are given: your mum, your mates, your team, though Anson’s is Spurs, not Arsenal.”

Boon and his family still live in Cambridgeshire. His mum’s side “is a big London working-class family,” he shares. “My mum definitely comes from a background of you didn’t have anything else other than family,” he says. “They didn’t have money. They just had each other.”

His dad is from a farming background and went on to become an amateur DJ, the original entertainer of the family. Growing up, Boon remembers always being busy. His mum would plan different after-school clubs each night and trips to their local cinema at the weekend.

Boon became so drawn to the idea of Hollywood as a child that he asked for a permanent reminder of the starriest place on Earth. “I remember when we moved house, when I was 12, I asked my dad to paint the Hollywood sign on my bedroom wall,” he says, perched on the edge of his chair, telling the story with the momentum of a compressed spring that’s about to go off. “Isn’t that funny just to think? I can’t explain it. I’m drawn to playing people.”

The ambition grew stronger and led to his first role at 14 in the children’s show All At Sea. At school, it made him feel different. His closest friends went into practical careers as tradesmen (although Mr Himesh Patel, a fellow British actor whose star is also on the rise, went to the same school).

The fire burned brighter when he dropped out of college to pursue acting full time. In a few years, his roles quickly scaled up. Background parts with big-name casts (a young prostitute in the Netflix series The Alienist, a petrol-station looter in the film Crawl, Private Cooke in Oscar-winning 1917) led him to a place where working with Hollywood royalty in his teens became almost the norm. The Hollywood mural in his bedroom had started to become the ultimate manifestation.

At 18, Boon was working with Ms Kate Winslet, Ms Susan Sarandon and Mr Sam Neill on Blackbird, where he played Jonathan, a teenager in a close-knit family coming to terms with his grandma’s terminal illness. His dedication became permanent after Blackbird. He lifts his sleeve, proudly showing the tattoo he shares with Winslet and Sarandon – a small outline of the bird perched discreetly on his bicep.

The cast regularly keep in touch on WhatsApp. Winslet and Sarandon remain mentors to him. Winslet, he says, “validated a lot of the desires that I already had in the ambition side, because she had them as well. She was a poor girl from Reading, who had all these aspirations and no way of achieving them and look what she did. She definitely inspired me and continues to encourage me to go for it.”

When Boon was first cast in Pistol, Boyle took him out for tea on the South Bank in London and guided him through the role. “We just discussed how we would attack this beast of a project and I was the only person cast at this point,” says Boon. Working with Boyle, he says, was the initial draw to the project. The two ended up creating a John Lydon fan club where they obsessed about details such as what Lydon’s mum would have cooked in specific scenes (from salad cream on leafy greens to when Lydon would have had his favourite snack, pickled beetroot).

Boyle says the actor “devoured” the research about Lydon, while Boon was spurred on by the director’s enthusiasm. He also embraced another part of the package – the outfits, from a bondage suit to leather trousers he wore at bandcamp. The style, which wouldn’t look out of place in the queue for Berghain, Berlin’s famously X-rated nightclub, suited Boon’s agenda. “The more outrageous, the more comfortable I felt because it complimented him [Lydon],” he says.

Capturing Lydon, whom Boyle describes as “one of the last, lasting originals”, was never about the singing or trying to be a carbon copy. It was about taking that leap of faith.

“Anson knew the details, the stories, the endless contradictions,” says Boyle. “And then he trusted his belief in Lydon, his passion for him as an artist, to help him make the leap to portraying him as flesh and blood.” That’s when Boyle saw star quality. “The highest compliment I can pay Anson is there feels like a unity there,” he says. “I feel like we’ve been in the presence of two of them for this past year, both highly original and both spurring us on to try and catch something of a moment and a man who actually changed our world.”

Boon remembers the moment it all clicked. “I was on stage and I could just see the crowd,” he says. “We were halfway through a song and I would realise what I was doing, all these contortions and spit flying through the air and wearing sunglasses and a bright pink blazer. The fire was really burning. I know I want to keep chasing that feeling, that this is what I love doing.”