Meeting Tim Westwood on a Monday afternoon in central London is a slightly disconcerting experience. It’s not merely that, after a series of complications, the venue for our interview has ended up being the enormously upscale, wood-panelled restaurant of a five-star hotel. It is, as Westwood notes, “not very hip-hop”, and as everyone knows, hip-hop is the passion that consumes Tim Westwood’s life: to the exclusion of virtually everything else, I learn over the course of the next hour. It’s also the rail-thin, crop-haired, 6ft 4in figure of Westwood himself.

Not that he’s a difficult interviewee. Quite the opposite. I really like him. He’s friendly, warm, funny, engaged and fascinating on everything from the excesses of hip-hop in the 90s – when Westwood used to hire a chef to cater for rappers visiting his Radio 1 show, among them The Notorious BIG, and dot the studio with bottles of Cristal champagne on ice and “newsreaders would have to come in and, like, sit on Jodeci’s knee to read the news with people spluttering on blunts all around them” – to the licensing issues that have effectively left him banned from DJing in the West End of London, “except,” he notes, “the one club where the crowd for hip-hop is entirely white”.

It’s just that Tim Westwood sounds, well, exactly like Tim Westwood. For some reason I’d got it into my head that his famous radio persona – that equally celebrated and mocked drawl, in which every other word seems to be slang or a catchphrase – was just that – a persona, that had less to do with hip-hop than it does the grand old radio tradition of Alan “Fluff” Freeman, Kenny Everett, Tommy Vance or Emperor Rosko: “personality jocks”, as they used to be known. As it turns out, I’m right about that part: “I could name some pretty household-name DJs and say to you, ‘Name some fly shit they say’ and you might struggle, mate,” says Westwood. “I’m not going to name them, because I don’t want to appear derogatory, but it’s like, well, they’re highly regarded, but what’s their fly shit that people say back to them? But when they say that shit back to me, when I’m out on the road and people say, ‘Yo, we’re going in baby!’ or ‘Now drop the bomb!’… it’s like you’re winning, family. Winning.”

My mistake was in thinking that Westwood might leave said persona at the studio door. I couldn’t have been more wrong. He addresses everyone – including me, the waiters and the maître d’ of the restaurant – as either “baby”, “fam”, “family” or “my brother”. There is talk of the ’hood and his crib, of getting lit and ripping down parties, and there is much use of the word “yo”. He’s the only person I’ve ever met who keeps switching to the majestic plural, or “royal we”, when talking about himself: “What did we get up to this weekend?” say, or “What we have here is a brunch situation,” he muses while perusing the menu. When his waffles arrive, he greets them with the words, “SMASH THAT!” When he suggests he’s toning things down because “we’re sitting in a fancy-arse restaurant,” what he means is that he doesn’t seem actively insane, in the way he does during, say, the interview with Young Thug on his YouTube channel, TimWestwoodTV. (Sample question: “Young Thug baby! In The UK! Motherfucking WHAT? Motherfucking WHAT? In the UK! Did you ever THINK THAT? Who the fuck let Young Thug in? Did you have any IDEA about that Young Thuggery love out there, fam?”). At nearly 60 years old, Tim Westwood, it seems, is always Being Tim Westwood, just at different volumes.

Westwood with Chuck D in the 1990s. Photograph: PYMCA/UIG via Getty Images

He doesn’t have much time for the suggestion that he might have constructed this persona in order to hide his real self behind: after all, he’s been broadcasting for over 35 years, 20 of them on the BBC – he’s currently on Capital Xtra – and all anybody seems to actually know about his personal life is that his late dad was the Anglican Bishop of Peterborough and that he was injured in a drive-by shooting in 1999, after a dispute with a south London gang that was trying to extort money from him.

“There’s no alter ego,” he says. “There’s no Clark Kent to the Superman. It’s still me, man. If I’m hanging out with the guys, my jeans might be low, I might be swearing, talking crazy. If I’m with my mum, I pull my jeans up and I don’t swear, out of respect for the situation. But it’s still me, brother. When I’m with the guys I’m still Westwood, when I’m with my mum I’m still Westwood.”

There isn’t any knowledge of Westwood’s private life, he insists, because there is no private life to have any knowledge about, nothing to excite any interest beyond his love of hip-hop, although the recent story in which he inadvertently broadcast his credit card details over Snapchat – “Baby looking forward taking you to dinner on Thursday. I appreciate you may wanna get nails, hair and a wax. Even some new shoes or a clutch bag. Use my card it’s black with private banking so there’s no limit, ” read the accompanying message – suggested there’s an other significant enough for Westwood to splash out on.

One reason he looks about 20 years younger than he is may be that he doesn’t usually drink or take drugs, “because I’m a frigging lightweight – back in the day when I used to drink and party up I was crazy, but there was a moment when I was hanging with [celebrated New York hip-hop DJ] Funkmaster Flex in a club, Long Island Iced Tea, blunt, being a flake, and I could see Flex was looking at me like I was a clown, so I put all that down and just focused, man”.

At least one reason why his aforementioned Young Thug interview is so berserk is because he momentarily broke with abstemiousness and took a few puffs on the rapper’s spliff beforehand. He dresses down, lives modestly in a one-bedroom flat and is unmarried and childless.

“If you’re in my world, you know everything about me. Because I … I haven’t got anything else in my life. Have I got a family? Have I got children? No. Have I got any interests in life? I like cars. I spend a bit of time with the car game, but that’s just bringing it home to hip-hop. As soon as my whip is ready to come out in summer, I’m out there pumping hip-hop, driving through the ’hood, looking crazy, you know what I mean?

‘Ripping it down in the club’ ... Westwood at work, c2000. Photograph: Des Willie/Redferns

“What you see is what there is. I don’t do anything else but this. Yo, I do a bit of office work to handle business. I film for Tim Westwood TV, there’s the clubs, the promotion of those clubs, that’s all we really do, there’s nothing else after that. And everything’s been a choice. The career has been a choice. It wasn’t like, ‘Oh, you know what I mean, I got a couple of baby mothers over there and a couple of baby mothers over there.’ No. My focus and my discipline is this. So what you see is really what you get.”

He says he has been like this since the early 80s. He had graduated from glass collector to DJ at London nightclub Gossips by promising he would bring 50 people down if they let him play, warming up for David Rodigan and the late Steve Walsh at the club’s reggae and jazz-funk nights. But it was the kind of nascent hip-hop then known as electro that really turned his head: “It was just powerful, felt like the voice of a new generation, it just resonated.”

Before long, he had his own, groundbreaking show on London pirate station LWR. You can hear clips of it online, striking not just for how subdued Westwood sounds – this was before his first visit to New York in 1985, where he met hip-hop radio DJs Marley Marl and Mr Cee, and under their influence, changed his presentation style to “match the energy of the music and the excitement of the clubs, start shouting and cracking that mic like I’m in a club” – but for the fizz of exhilaration they convey, the sense of being absolutely at the cutting edge of music at that moment.

It wasn’t just the music Westwood liked, but “the culture, the hip-hop lifestyle”. At risk of playing amateur psychologist, it’s tempting to wonder if hip-hop’s penchant for swaggering self-improvement – or as he puts it, “the aspirations of hip-hop … the culture of the street and the struggle and the life, you know, from nothing to something” – didn’t chime with him, white clergyman’s son from Lowestoft or not. His childhood was troubled. “I was out there. Dyslexic when dyslexic was, like, ‘you’re stupid’ not ‘you’ve got a problem’. Useless at sport, useless at woodwork, metalwork, bottom of the class, failed all my exams with Fs, why they even asked me to do A-levels I don’t know but I got Us, which meant Unclassified. Like, I came from that. Lost, just lost, not being positive in anything I was doing, out there, out there. And I suddenly found my passion, my dream.”

It wasn’t a surprise that Westwood became a big DJ in the first place. He was an early adopter and obsessive fan of a music that would go on to take over the world, and furthermore clearly a very savvy operator indeed: he was a co-owner of Kiss FM, the pirate station he defected to in 1985 and which subsequently went legal and started his own production and events company not long after, years before Radio 1 came calling. More startling perhaps is the fact that he’s still doing it 35 years later, still on radio, still, as he puts it, “ripping it down in the clubs, making that party lit”, still eagerly promoting his nights and putting out compilation albums, still bellowing “motherfucking WHAT?” at whoever the latest hip-hop or grime or UK drill sensation is on his YouTube channel (“a monster, half a million subscribers, something like a third of a billion views)”, which he says he started partly because he wanted controversial London rapper Giggs to perform a freestyle on his show and “he was banned from the radio, he literally was not allowed into the radio station building for an interview or to perform”.

He looks genuinely baffled when I ask if it ever gets exhausting trying to keep up. “It’s the easiest thing to keep with, to have the energy for, because this is it, man. You’ve got to understand, I have lived a blessed life. Like, I was shot at close range, my friend had his kneecap blown off, a bullet went through the back of my seat an inch from my spine, a bullet went through my arm and missed the three nerves which would have left me paralysed – am I not blessed?

“Everything I’ve experienced, I’ve been able to win and enjoy and have that love. Why would I want it any other way? It’s been the most amazing experience in my life. I keep it relevant. The music’s kept me relevant. And that’s why we’re still out there, you know, hot on the radio, hot in the clubs, hot with the albums. Yo man, like we’ve always been the hardest in the game. Legends live for ever, and we’re one of the last real ones.”

• Westwood: Hip Hop Club Bangers is out now.