Although Mr Michael Omari, better known as the rapper Stormzy arrives at the MR PORTER photoshoot accompanied only by his manager, there’s every reason to believe that in a year from now he’ll be moving with a posse in tow. Stormzy stands at the cusp of fame. In 2015 he had a UK hit with “WickedSkengMan4”, the first freestyle in history to enter The UK Top 40; played live in Europe, Australia and Africa; appeared on stage with Mr Kanye West at the Brit Awards; and won two Mobos for best male act and best grime act. He also ended the year tilting for a Christmas number one with his YouTube smash “Shut Up” (15.1 million views at the time of writing). The 22-year-old has rare talents, a winning openness and his sights are set high; when asked about the scale of his ambition he replies, “We’re going for Beatles status, that was always the plan.”

Standing 6ft 3in tall, Stormzy is physically imposing, but he’s approachable, good humoured and more than happy to laugh at himself. His attitude serves him well, and bears little relation to the stereotypical moody rapper from a tough neighbourhood – in his case, Thornton Heath in south London. He once tellingly rapped, in a memorable freestyle on the UK’s Radio 1Xtra station, “I swapped my beef for a future.”

Grime is the uncompromising British rap genre that developed out of the garage dance music of the late 1990s and early 2000s. Stormzy’s recent chart hit means he has now joined emcees such as Wiley, Skepta, JME, Wretch 32, Kano and Lethal Bizzle, who have all enjoyed mainstream success. However, grime’s biggest name remains Dizzee Rascal, who won the 2003 Mercury Music Award with his debut album, was one of five grime artists to have a UK number one in 2009, and performed at the opening ceremony of London’s 2012 Olympic Games.

“I was probably 10 or 11,” Stormzy says, remembering when he first started to emcee. “Me and my friends were all rapping. I was listening to people from my area, like Giggs, Konan and Roadside G’s.” That grime is rooted in English life, rather than American hip-hop culture, is central to its appeal, and it shines through when Stormzy uses the word “arse” rather than “ass” in his rhymes. “I need to sound British,” he says. “You never hear an American trying to sound English, so why am I going to try to sound American?” It’s clearly something they respect across the pond; last year Drake inked himself with the initials of grime group and label Boy Better Know, while north London MC Skepta sold out a triumphant US tour.

Grime artists have been criticised in the past for rejecting their musical roots and courting house or pop to achieve chart success. While his accent and vocabulary won’t change, Stormzy will be spreading his musical wings on the debut album he’s currently recording with producers SOS, AKA Messers Mo and Mikey Samuels. How will he overcome the inevitable resistance among some of his original fanbase to a change in his sound? “I need to make sure [the music’s] amazing. I wouldn’t go poppy, because that’s something I don’t understand, but I’ve been listening to R&B and soul my whole life. It’s part of me.”

Mr Kanye West isn’t the only established name keen to be associated with Stormzy. The Londoner recently posted a photograph of himself in the studio with actor Mr Idris Elba, who’s a part-time DJ and rapper when he’s not starring in movies such as Beasts Of No Nation and TV shows The Wire and Luther. “He’s one of those people you can learn so much from,” says Stormzy. “Not just working on a track, but in life.” Meanwhile, Stormzy is presumably learning about corporate life from his work on the Apple-owned Beats 1 radio station – he presents his own show called #MERKY every Friday night – and Google, which recently featured him in an advert for its Chromecast service. When asked if his connections with two of the biggest names in Silicon Valley are part of some grand plan, Stormzy laughs. “No! That’s why it’s so sick – I get as confused as everybody else. Sometimes I think, ‘What do they want with me?’” Does he worry that he could lose something of himself as he moves from the purity of the grime scene towards the mainstream? “If I turn up and I’m myself, I ain’t got to worry about someone misinterpreting me, or being made to do something I don’t want to do.”

He’s certainly free from record company pressure. When asked about labels, his answer is totally at odds with the manufactured nature of today’s corporate music industry. “We release our records ourselves. We release them under… I can’t remember… it’s Stormzy. I don’t think it matters, it’s not that big a deal.” What does matter is that his circumstances have improved. “My reality has totally changed,” he says. “It’s a fairytale story. From proper humble beginnings to… well, it’s not extravagant. I said that as if I’ve now got a mansion! But it’s nice now, even this photoshoot… how did this happen? Just the other day I was taking pictures on the estate!” Now when Stormzy is photographed on housing estates, it’s by film director Mr Noel Clarke, who has given the rapper a leading role in his forthcoming film Brotherhood.

So, is it fair to say Stormzy doesn’t normally wear Balenciaga? “I’m proper simple,” he says. “I just wear whatever. When I was invited on Jools Holland, and that’s a prestigious TV show, I was thinking, ‘What do I wear?’ But I thought there’s no point thinking about it. If I have to think about it, then I’m not being myself. So I wore what I like, which is a tracksuit.” Just another example of the authenticity that’s brought him a long way from Thornton Heath, and promises to take him much, much further.