With hundreds of venues, riffs blaring from every corner and more indie bands per square inch than anywhere else on the planet, the SXSW festival in Austin, Texas must be seen by most emerging musicians as the promised land. Ben Howard, however, is not impressed. "I hate it here," he says. "You don't have time to think. The people are mental! And it's not helpful for musicians at all – you see everyone lugging their own gear everywhere, it's a nightmare."
This is not the kind of on-message nicety we were expecting from Howard, whose gentle, finger-picked songs go hand in hand with a love of surfing and a (usually) laidback manner. But then, as we'll find out over several mid-afternoon whiskies in a hotel lobby, Howard does enjoy a good rant – especially when it comes to his critics.
Besides, it's not as if he's genuinely unhappy – how could he be with things going so well for him right now? Today, for instance, he found out he had sold out the Bowery Ballroom in New York. Yesterday he headed out to a studio with his Communion label gang to drink beer in the sun and record a cover of John Martyn's "Over the Hill". Later on he will play a gig at St David's Episcopal church in Austin that will have fans singing in the pews – a reaction that suggests the London-born singer-songwriter won't struggle to win a following in the US.
Back home, things are looking even rosier. He has packed out the Shepherd's Bush Empire two nights running, sold 130,000 copies of his debut album, Every Kingdom (which went Top 10), and – unusually for a folkie – seems to be followed around the country by an army of screaming girls – a one-man One Direction, if you will. Yet if you mention the name "Ben Howard" to people, many won't have even heard of him. This is the first big newspaper interview Howard has done; almost all of his success has come through relentless gigging and genuine word-of-mouth buzz, especially from within the surf scene which Howard, a keen surfer himself, is often linked with.
"I think being involved in that scene helped because surfers travel," he says. "I get messages from Paraguay and Puerto Rico asking when I'm coming there – surfers are always in these far-flung places."
You've basically got the world's best street team?
"Totally! We were selling out venues, not just in London but also major cities in France and Germany before labels had even noticed what we were doing."
When did he realise it had got massive? "It still happens. Shepherd's Bush was a proper childhood dream."
Those Shepherd's Bush shows in February were notable for the large contingent of delirious teenage girls who spent the gaps between songs screaming to the point of nervous meltdown. As happened with Ed Sheeran, the younger fans seem to identify with Howard's everyman image and like the fact they feel they discovered him themselves.
But did Howard ever bargain for screaming teen fans when he started out?
"It's always something I've been scared of, to be honest," he says. "I've always wanted to play shows to people who really love the music and get what you're doing – the screaming I just find… funny."
Does he care about his image as a heartthrob? "Does it look like it?" he says, pointing to his Quiksilver T-shirt and recounting a story of the time he played Bestival in an anorak and his girlfriend's jeans. "If I tried to be fashionable I'd look like a twat."
It's not just teenage girls who love Howard. At Shepherd's Bush I spotted plenty of burly blokes, shaven of head and clutching pints with the odd tears in their eyes. This, it turns out, was no anomaly – Howard's fanbase is pretty diverse.
"I remember one time up north a huge skinhead came up to me in a bar after a show," he says, grimacing at the memory. "I tried to avoid eye contact but I knew he was coming straight towards me. Then he said: 'Mate, I just wanted to say, that was fucking wicked.' I thought he was going to punch me! Those moments are little gems – knowing your music has touched a wide range of people.
How obsessive have fans got?
"A few tattoos of lyrics. It's a huge compliment but it puts pressure on you as well. I always worry about what I'm doing with my life because music is a selfish pursuit. But we get so many letters from people who've been dealt really shit hands, and to be in a position where you've helped them in some way, that's an amazing privilege."
Howard looks wistful and orders another Scotch before going into his musical evolution. He was a "noisy kid" who'd make up songs and sing them in the car. His musical education came via James Taylor, Paul Simon, then the likes of John Martyn, Bob Dylan and Joni Mitchell. By the time he came to record his album in a mouse-ridden barn in Devon, he'd already had an EP out while at university and had plenty of practice touring Europe off his own back.
Howard is midway through his third whisky now (not to mention the margarita he had before I met him, and it's not even 3pm yet), so it seems he might have softened up enough to enquire about a certain elephant in the room. Howard believes the UK music scene is on fire right now – and namechecks Adele and Mumford & Sons as leading the fight – but this British renaissance has come under fire from some critics. Back in October, Peter Robinson wrote a piece for the Guardian in which he labelled the likes of Ed Sheeran, Mumford & Sons and Adele as "the New Boring", symptomatic of a culture that ignores flashy stars and innovation for the safe comforts of plainly dressed men and women singing retro music.
It's hard to deny that Howard would fit into that scene – so how does he feel about his musical style being labelled boring?
"I always rise to stuff like that," he says with a wicked grin on his face, before the ranting begins. "Look, when Mumfords came out that was the freshest thing on the music scene by a million miles. Someone playing a double bass and a banjo? That's cool.
"British music at the moment isn't boring. Adele has taken over the world and she's not a pop star – she writes songs and she can sing. Same with Mumford & Sons. They're all playing acoustic instruments rather than playing synths and being told what to do. I've never been a fan of all the R&B and vocoder stuff you hear on the radio."
Is there not just as much skill in making a synthesised pop record?
"There's force-feeding people synthesised music, then there's a skill in technically being able to play an instrument, even if that is some electronic pad."
Surely to a lot of audiences the technical side can be rather dull…
"True," he concedes. "If that's all that mattered we'd all just listen to jazz. I guess I'm talking about a 'heart and soul' side. And that's where 'real' music takes over… people who care about what they're singing about.
This talk of "real music" might be tiresome, but deep down Howard isn't on the frontline shouting; he'd probably sooner not have been drawn into the debate in the first place and be left to concentrate on his music.
"I'm one of those artists who doesn't really believe in fame," he says before he leaves. "You can be a normal person these days, you don't need celebrity appeal. Your mate [he means Robinson] might say that's as boring as piss – but I couldn't give a fuck what he says!"
And with that, this word-of-mouth star with an army of delirious fans blends seamlessly in with the crowd on Sixth Street in Austin and disappears.
Ben Howard's new single, Only Love, is released on 14 May on Island