I meet Stormzy in a beautifully appointed recording studio in a chi-chi area of London. He stands out, but then he would anywhere. Stormzy, real name Michael Omari Jr, is a can’t-hide 6ft 5in in his trackie bottoms, black socks and slides, plus a T-shirt that, unexpectedly, has a picture of Louis Theroux on it. (“Louis Theroux is a G!” he insists. “I take my hat off to him, he’s good!”) Stormzy makes music, mostly grime, and in his YouTube videos, he towers over his crew, dominates the frame like a giant. When his PR suggests he try on a sweatshirt he’s been sent, he makes a face. He knows it won’t fit. He’s right. The arms only reach halfway between his elbows and his wrists.

Despite his height, and his suck-teeth video demeanour, there’s a cheekiness to Stormzy. When he MCs, there’s always a line or a facial expression that makes you smile – he farts at the beginning of WickedSkengMan 4, and in the freestyle video, he keeps laughing – and in person, he is friendly and engaged. There’s no doubt that Stormzy could be stroppy if he wanted; it’s just that, at the moment, he doesn’t want. Too busy. Too focused.

A few days ago, the tickets for his March-May UK tour went on sale. The two shows in Brixton, London sell out in seven minutes (he adds another date; it sells out too); within 12 hours, nine more venues, from Belfast to Birmingham, have no tickets left. His first album, Gang Signs & Prayer, will be released on Friday and is set to be a big deal: his singles have been getting huger, beating X Factor winners in Christmas song dust-ups, and he cancelled a series of gigs last year to finish it. Now, pre-sales have Gang Signs on target to hit No 1. Big for Your Boots, the lead single, came out last week and went in at No 8. He laughs. “I remember thinking, if SkengMan goes top 40, I’ll have a party. And I did! Now, I’m not even thinking about it.”

Stormzy’s climb has been rapid, a rocket shot into the sky. He’s so hot right now, his tweets have become front page news (this week, he tweeted a picture of the front door of his Chelsea flat, bashed in by police after reports he was burgling it: it made the cover of the Evening Standard). Still only 23, just four years ago he was in a job he hated, as project manager on an oil rig, watching Wiley videos in his lunch break. In 2013, he won a Mobo for best grime act, and then again in 2014. In the same year, Wiley tweeted that Stormzy was the “#1 grime don in this new era” and asked him to “take it to where we couldn’t my brother”. When Kanye brought the UK’s biggest grime stars on stage at the Brits 2015, Stormzy was there. He won Mobos for best male and best grime act that year. In Christmas 2016, he grabbed himself a No 8 by rereleasing his YouTube track Shut Up. I saw him perform at the Skepta-JME Brixton show around that time. He only did Shut Up, but the crowd went bananas. You could see he was about to become even bigger.

But to do that, you need an album, and making an album is not easy, especially not for one-man-and-his-mic grime artists. Stormzy, who is far from just that, chose to join forces with Fraser T Smith, a Grammy-winning producer known for his work with Adele (a line in Big for Your Boots: “I was in the O2 singing my lungs out/ Rudeboy you’re never too big for Adele”). The album took them 10 months from start to finish, which isn’t bad going. This is Smith’s studio, and he pops in: an urbane fortysomething who’s just come back from a trip to South Africa and talks excitedly about the musicians he met there. Stormzy wanted to work with Smith because he knew that they were different, but also similar.

“What I do,” he says, “is not Fraser’s forte – as in, hard-hitting grime. But I wanted to marry my ambition with somebody who had that same ambition, someone who would make an album showing the world how incredibly beautiful a grime artist can sound, sonically and production-wise. How polished grime can be. And then also, I was intrigued by what we could make. I’m very vocal in the studio, I have a clear artistic vision, and I know Fraser has exactly the same. I thought, ‘This could be a total disaster or it could be the most incredible beautiful thing’.”

We talk through each track. Though Stormzy broke through with his diss tracks – Not That Deep (“Your postcode don’t make you a gangster/ You’re not bad, your area is”), Know Me From (“I come to your team and I fuck shit up/ I’m David Moyes”), Shut Up (“Tell my man SHUT UP”), Big for Your Boots (“Got my big size 12s on my feet/ Your face ain’t big for my boot”) – he has a more varied back catalogue than you might imagine. He sings, he isn’t frightened of a ballad, he’s covered a Justin Bieber song. And Gang Signs & Prayer references this. There are 13 tracks on there, plus a few extra bits, and as Stormzy goes through them, he talks of vulnerability, uses words such as “pure, touching, reflective” as well as “explicit, raw, horrible”. Sonically, there’s R&B in the mix, afrobeat, a gospel choir, live strings… There are definitely a few bangers: Shut Up and Big for Your Boots are on there, plus Cold, which he teased last year on 1Xtra shows, and Return of the Rucksack, which I hear (it’s great). Still, this isn’t a simple album. The subject matter isn’t as straightforward as you might imagine. A track called 100 Bags sounds like it’s about drugs or money (“Ghetts came in and he was like, ‘100 Bags!’ And I was like, ‘Before you start giving me gun fingers and salutes, you’ve got to hear it first’”) but is, instead, a “sad tribute”. When I try to guess what BBYG Part 1 might stand for (I say embarrassing things like Better Bring Your Gun), Stormzy says no: it’s Blinded By Your Grace.

“It’s about God,” he says. “One of the things that I’m most impressed by, in God, is the grace that he has. No matter what we do, there’s always this, “OK, it’s fine. I understand.” That’s not to say I can go out and do something bad… But just that knowing that someone’s got you throughout anything, and they’re not going to judge you, they’re just going to understand your situation. That grace.”

Actually, Stormzy’s first memory is of “Sunday, going to church”: his mum, Abigail Owuo (she appears in the video for Know Me From), was a parishioner of a Pentecostal chapel in Streatham. “It was just what you did on a Sunday,” he says. He has a strong faith, but he admits that he lost his way for a time. “I was a good boy in primary, but then I was a bad boy.”

The last track of the album, Lay Me Bare, gives a few hints as to why. Stormzy calls it a “whirlwind of emotions”, and it moves between resignedness, intimacy, regret and anger. The anger is mostly directed at his dad, who wasn’t around at all when he grew up. Father to young Michael and his two older sisters, Stormzy’s dad worked as a cabbie in Croydon. The few times Stormzy had contact with him was when he asked his mum for money and she gave him his dad’s number and told him to text him.

Woke up to Feds destroying my front door coz apparently I'm a burglar who burgles his own home. @metpoliceuk need your bank details still pic.twitter.com/fGH1fsePHv — 24/02 (@Stormzy1) February 14, 2017

“And I remember going to the cab office and picking up an envelope and there being £20 in it. That happened twice. At the time, I thought, ‘Oh, £20, I’m good.’ But now I’m thinking… mad. I’m not bitter towards him, it’s more, ‘I can’t respect you as a man’. Because now I’m a man. And even if I was the shittest prick on earth and I had a child… I think, ‘You didn’t even do the bare minimum. You didn’t even get me a birthday card.’”

Anyway, Lay Me Bare gives a space for some of the disdain he feels for his father. He says it’s the only track on the album that felt cathartic; it was made in one day, during the final week of recording. The rest of the album wasn’t like that. He had an idea in his head – “like a jigsaw in my mind, but I’d already completed the puzzle” – but the process was hard. He’s very proud of the result. He knows it’s more than most people expected of him. He says: “This album is good, this is incredible, this is heartfelt, this has been put together so well, so strategically, so neatly, so creatively – so respect me the same way you’re going to respect a Frank Ocean or an Adele.”

This might sound cocky in print, but not so in real life. When Stormzy says it, it sounds like a statement, rather than an assertion.

“I find it strange and uncomfortable to aim for anything less than the greatest,” he says. “That doesn’t even make sense for me, that. If I was going to be an engineer or I was going to be a baker or I was going to be a fireman, why would I not aim to eventually be the greatest at my job? I’ve never understood why I should just try and be the best rapper in London, or even the best rapper in the UK. I don’t want to be the best rapper in the UK. I want to be the best artist in the UK. That takes my competitors from 20 people to 100 people, because now they’re indie bands, female singers, soul singers, legends, rock icons that I’m competing with. In my head I’m like, ‘Why can’t I compete with them? Why can’t Stormzy from south London do that as well?’”

Stormzy grew up in Norbury, near Croydon, with his mum, two sisters, Rachel and Sylvia, and a younger brother, Brandon. He and Brandon shared a room until Stormzy was 18, when Rachel moved out. His home life wasn’t unhappy, but it wasn’t cosy.

“We always had the family tightness of ‘We’ve got each other no matter what’,” he recalls. “So if anyone needs money, if anyone’s got beef, like down the road and there’s fighting, we’re all going to run out and beat the person up… We had that. But in terms of the whole eating dinner together and going on family holidays, there was none of that. That whole friendly, ‘Oh, you’re my sister’… there was none of that. It was individuals operating in the same house. I never had that home of having posters on my wall and having trainers lined up, it was just… somewhere I slept. I would go out, do whatever I’m doing, come home, eat food, talk to one or two of my family and then fuck off again.”

He says he was around 10 when he started playing out, “causing trouble”. And he was rarely indoors during his teenage years. The other day, he happened to be driving around his old streets, and he decided to drive the route he used to do as a teenager: “From my mum’s to my best friend’s house and then walking to the block to stand up there in the freezing cold and chat shit and smoke weed and sell whatever, and from there walking all the way back.” He couldn’t believe the distance. “Miles,” he says. “Literally miles. I was a road rat.”

Why were you out all the time?

“Because I think my home reminded me of the poverty I was in,” he says. “We had a small house, it wasn’t the best of houses, not in the best condition, and… it wasn’t comfortable for me to be there and just chillin’. I would go to my friends’ houses and they had these nice, beautiful houses, and with my house I felt none of that. So I was always out, doing things to get money.”

He did well at school until after his GCSEs. He was smart, so he could mess around and still ace exams. “I always figured out how to play the borderline,” he says. “I was as horrible and as menacing and as troublesome, and as flipping… annoying as I could be. Just playing that line of you can’t really expel me.”

And though he was suspended, on occasion, he wasn’t expelled until he went to sixth form. The school he was at, Stanley Tech, wasn’t a good one, and, when he was in year 10, it was taken over to become a Harris Academy. Harris schools are known for their discipline: Stormzy remembers being in sixth form when his mobile went off. The teacher said: “Can I have that?”, “And I was looking at him going, ‘Of course you fucking can’t’.” He got suspended for that, and, after “a string of offences”, was eventually expelled. Still, he got himself to college, and sat a couple of exams, including his English AS-level. “But I remember thinking, ‘I’m not about to do three more of these and then five more again in May’. So I just got up in the middle of the exam, walked out, got on the train and went home, and that was the last of it.”

Stormzy performing at the V festival in Chelmsford, August 2016. Photograph: Rex/Shutterstock

Stormzy has dismissed his old behaviour as “fuckeries” – he’s not always clear about what he got up to – but it’s safe to say he was a troubled, troublesome youth. Why, when he was good as a young kid, did he go bad?

“I think I was always bound to,” he says. “It’s a debatable one because people say, ‘Oh, yeah, but I grew up in the same area and I didn’t’ but I think just growing up where I’m from, the secondary school I went to, the people I was surrounded by… It was just all the recipes for like, ‘You’re gonna do this.’ Like, ‘This is your way.’”

From his school year, and the one above, he knows around four or five boys who are in prison for murder. Yet he and most of his friends weren’t what he would call real gangsters: “You’re not going to knock on someone’s door and put a bullet in their head. A lot of these kids haven’t got that in them, as 95% of humans don’t, because you’re a human. There are a lot of good kids caught up in it.”

But they still got up to all sorts of wrongness, from dealing to fighting to stealing.

“When you’re in that situation,” he says, “it feels normal. Like now, I wake up and go to the studio and make music, and that feels normal. Back then, I’m waking up, I’m hitting the roads, I’m going to get drugs, and I’m going to sell drugs, and I’m linking up with the mandem later, and we’re going to figure out how to make some money tonight, where we can rob and who we can move to. And then you go home and you sleep.”

When he was 19, Stormzy changed. He can’t pinpoint an incident that made him alter his course, but he knows why he did. “Somewhere along the line, I figured out that this isn’t a logical option. I realised that being on the streets is very bad for business, very bad for going forward in life, and very bad for success – and success has always been the biggest thing for me.”

Everyone has a different idea of success, of course; and for a while, he followed his mum’s dreams. After college, he got on to an apprentice course and ended up as a project manager at an engineering firm, working on an oil refinery off the south coast. But it didn’t fit. He thought hard and realised that he wanted to try music. For a while, he combined the two: writing while he was working, calling in sick because he had a radio gig. But eventually, the pull of music became too big and he quit.

He’d actually been MCing (“spitting bars”) since he was around 11, when he’d turn up to his youth club, Rap Academy, and grab the mic. Though other kids liked US rap, he was only interested in grime. Dizzee Rascal’s Boy in da Corner came out when he was 10. It blew his mind and, after that, he got into Wiley, Kano, Lethal B... He chose his nickname when he was 13: “I just thought, ‘What’s cool? A storm.’” Sometimes it makes him laugh when a DJ says it on the radio, because he was so young when he made it up.

Grime has fallen in and out of favour in the past decade and a bit, and Stormzy thinks it’s now at an interesting stage. He talks for a long time about where it can go, how it’s in its second generation and that means new grime artists can experiment, break it out of its original template. Some, such as Novelist, he thinks, will stay pure; others, such as AJ Tracey, use trap and drill beats; or, like Stormzy, will sing and make R&B. He sees grime developing like hip-hop has done in the US, where artists as different as Drake and Kendrick Lamar and Young Thug are all seen as part of the scene, and where hip-hop has become the national music. People are protective over grime – “and rightfully so, because a lot of people have got their hands on it and messed it up and artists have bounced in and out of it” – but he feels it’s strong enough now for the new generation to experiment. “A lot of it is going to be wrong because it’s new, but we shouldn’t be scared to do it.”

One of the aspects to grime that Stormzy has embraced is its DIY ethos. Dizzee’s original go-your-own-way independence has been picked up by others, including Skepta and JME, and Stormzy himself was the first ever unsigned artist to appear on Later… With Jools Holland. He likes his independence, because he enjoys being involved in every aspect of his career, but he doesn’t think it’s for everyone. Wretch 32 is an example he gives of a grime artist who is signed to a major label and it works.

“I always say an artist, a musician, is like a car,” he says. “And cool, you’re the engine and you’ve got all these ideas. But someone has to do the alloys, someone has to make sure the tyres are up, someone’s got to make sure the boot’s working, someone’s got to do the air con, all these little things. I’ve been used to doing Shut Up and putting it out and, ‘Woo, fucking hell!’ But now? You want to be an internationally known artist? You’ve got to sort out your shit in Japan. You got a radio plugger over there? And you thought putting billboards up was free? No, that’s going to cost you a lot of money. Have you got that money? Are you willing to dip into your own pocket?”

If you want to be an internationally known artist, you have to think about the international environment. And Shut Up was released into a world that was different from today’s; post-Brexit, post-Trump. Stormzy has expressed support for Black Lives Matter in the US (“I’m not going to wait until something happens to me or my loved ones before I speak out about it,” he said to iD’s Hattie Collins last year), and he’s voiced approval for some of Jeremy Corbyn’s ideas too. But actually, he says, though he thinks internationally in terms of his art, when it comes to his political message, he stays closer to home.

“The main thing with me is my young black kings,” he says. “And this ain’t to ostracise young black women or old white men, or Asians, it’s not to ostracise anyone, it’s just to say, ‘OK, young black men in my country, when it comes to who is going to achieve, you are always the very last.’ So I need to talk to my young black kings, because I’m one of you, we who are always last. And I say to them, ‘You are sick, you’re nang, you can do this. You’re better than anything anyone’s ever told you that you are. You’re just as powerful as me. You’re just as sick as me. You are just as ambitious, and you can be just as creative and as incredible and as amazing as me, Kanye West, Drake, Frank Ocean, all these people that you see. You can do that.’

“And that message is big. If I connect that with 10 people, that’s a CEO, and that’s a political leader, and that’s a musician who’s going to be the next Michael Jackson… all these things. So hopefully I’m going to connect with the person who one day is the political rival of Trump.”

Stormzy thinks big, but he doesn’t forget his small start. He has a screw-face in his videos, but he also has his girlfriend, his family, other artists, his local chicken shop. He represents.

“Yes. Some people are touchy when you talk about young black men, because it’s so taboo. But it’s like, no, I’m here, and all I’m saying is this: ‘You lot, my young black kings. You can do this as well.’”

Gang Signs & Prayer is out on Friday on #Merky Records. Stormzy’s tour starts in Belfast on 31 March