For most of the past half decade, Mumford and Sons have been on the road. Four 20-somethings on a tour bus for five years. The things they must have seen. The things they must have done!
"Once, Ted and I turned all of the furniture in our hotel room upside-down," says Ben Lovett (keys, accordion, 26, the brown-eyed, dreamy Son), tugging at his frizzy, woolly hat.
"That was pretty, um, calculated. We weren't even that drunk, we just had a joint moment of freaking out. And then in Colorado, two days later, we were both staring off into the distance and we realised that we were both feeling guilty about some poor housekeeper having to go into that hotel room and put it all back."
"Yeah! We're mentaaal..." drawls Winston "Country" Marshall (banjo, Dobro guitar, 24, the wild-haired, tattooed baby Son), half throwing a cushion off the hotel sofa before thinking better of it and patting it not quite back in place. "We'll tidy that up before we leave," frowns Lovett.
Ah, Mumford and Sons. The west-London quartet who made waistcoats, banjos and sincere yodelling mainstream. Purveyors of rousing emo-folk and hoedown-pop, they've been labelled, variously, one of the biggest success stories in rock (Rolling Stone), Coldplay for hillbillies, and "a load of retarded Irish folk singers" (the Fall's Mark E Smith, in typically charming form).
They might not be wildly rock'n'roll - "I don't understand how those old bands did it," says Marshall. "We worked out early on that if we did three gigs in a row and went out afterwards, we'd lose our voices. We know our limits " - but in the past year, Mumford and Sons have quietly, politely, ever so British-ly, transcended their limits to become superstars.
Their 2009 debut album Sigh No More has now gone four-times platinum. Last year they became the first British band since Coldplay to sell a million copies of one album in both the UK and the US, were nominated for six Grammys and backed Bob Dylan at the ceremony.
They have just completed a triumphant tour of America, playing to 20,000 a night, and earlier this summer, Bruce Springsteen hauled them on stage to holler along on Hungry Heart. "The best day of my life," declares Marcus Mumford (vocals, mandolin, 25, the waistcoat-wearing, Steinbeck-reading charismatic leader), who also squeezed in a wedding to Hollywood darling Carey Mulligan this year.
In March, they were invited to play at the White House. "We love Obama," says Mumford. "We shook hands and he said, 'congratulations on all of your success.' And I said, 'congratulations on all of your success'. Heh heh heh."
So, it's been quite a year for Mumford and Sons. Today, they are holed up in the Soho Hotel, London, drinking black coffee and smoking out of the bedroom window like naughty sixth-formers. Next week the tour bus rolls on to America, Canada, Australia and New Zealand.
Five years ago Mumford was an aspiring drummer in singer-songwriter Laura Marling's band. Back then, Ted Dwane (double-bass, 28, the willowy, thoughtful, grown-up Son) was still lugging his battered double-bass from gig to gig with dreams of enrolling on a jazz course. Lovett was playing with indie band Hot Rocket. And Marshall, a dreadlocked trustafarian (his father, Paul, runs the multi-millions hedge fund Marshall Wace) was playing in a ZZ Top tribute band and running a tiny music club.
It was here, via various schools and church summer camps, that the quartet coalesced. Dwane and Mumford, having been fired from Alan Pownall's band, started playing for Marling with Marshall. They poached Lovett and at the end of 2007, Mumford and Sons was born.
They emerged in a precocious cluster of talents - Marling, Pownall, Charlie Fink's Noah and the Whale, and Johnny Flynn - which came to be called the west London new folk scene. "And which famously never existed," grumbles Mumford, who dated Marling after she split from Fink. "It was more of an open community than a scene - which I've always thought of as an exclusive word."
Somewhere along the way they outstripped west London and went global. "We're not a cut above the rest. We never have been," says Lovett, who still runs his Communion nights for aspiring acts. "And I can't imagine us finding the time to ever be. We see ourselves on a par with our peers, whether they are playing to 10 people, or a hundred. At times I get upset that we're not as connected as we once were to it." Still here they are, launching their second album, Babel.
The first single, I Will Wait is classic Mumfords, a rollicking, heartfelt shanty with a roar-along chorus. It could be about Mulligan - she and Mumford were childhood pen-pals through their respective churches before they met again at a gig in Nashville last year and married five months later. It could, given the opening lines - "And I came home /Like a stone /And I fell heavy into your arms" - be about being on the road. It could be about salvation - "I'll kneel down/ Know my ground/ Raise my hands/ Paint my spirit gold".
Like most Mumford songs, it could be about anything, really. And, like most Mumford songs, it makes most sense when played fast and furiously to a rapturous audience. The Mumfords manage to be lots of things to lots of people. "Even if the songs aren't necessarily about exactly what you're feeling," says Lovett. "It's a good one-and-a-half-hour therapy session."
Babel won't alienate their core fanbase, in any case, featuring plenty more frenetic fingerpicking and bruised hollering. Still, it took its time, thanks to the band's reluctance to come off the road. They finally recorded it last year between Nashville, London and Lovett's parents' barn in Devon.
"It was like..." says Mumford, "a beast that we had to tame." The title is an overt Biblical allusion from a band who have so far hedged their Christian credentials. Mumford's parents are the leaders of the British arm of the conservative, evangelical Vineyard Church. Is this a statement of how important religion is to the band?
"No. Religion is not at all," says Mumford, scowling at his cowboy boots. "Faith is. We each have individual beliefs. Our values are pretty shared otherwise we wouldn't do well on the road. Faith is a more spiritual thing."
"I've always thought of faith as an acknowledgment of not being the biggest thing in the universe," says Dwane.
"We don't really claim to have any answers," says Mumford. "We're just exploring shit as much as anyone else is."
Tracks like Hopeless Wanderer and Reminder are suffused with the road and longing for loved ones left behind. Mumford has been on tour since his wedding (last April, on a farm in Somerset). "It's complicated but it's worth it," he says of marriage to Mulligan.
"There's been lots of change in all of our lives but we're still just working. There's a cost to it certainly. But there's a cost to any job."
Relentless touring has helped them to break America. Along with Adele, they're now the hottest Brits on the Billboard chart - not bad considering four years ago saw them sneaking a ride in the back of Marling's van, playing support gigs "to 12 people in Minneapolis".
They have preserved their homespun ethos and wooed a nation, one state at a time. Or, as Mumford puts it, "We're fat, sweaty and we try hard."
Who: Mumford and Sons
When and where: Vector Arena, Auckland, Nov 2; Wellington Town Hall, Nov 4
Also: Second album Babel is out this week.