With a fourth album brewing, and their concert film Dust And Thunder just out, Mumford & Sons are keeping busy. And that’s just how they like it, Marcus Mumford tells Andy Welch

SOMETIME in 2014, two years after releasing their record-breaking second album Babel, Mumford & Sons announced they were taking a break.

They'd been hard at work for the best part of five years, had toured the world several times over, won Grammy and Brit awards, and had the accolade of 2012's fastest-selling album under their belts. They deserved a rest.

However, just over a year later, they returned with Wilder Mind, which, like Babel, went to No 1 in both the UK and the US. Then, after another hugely successful round of touring, they once again hinted at taking a break, but... "We're pretty restless and we've got very short attention spans," says the band's Marcus Mumford, 29. "I think that comes across in our music. Even on stage it's a microcosm of what we're like - we change instrument if we do one thing for too long."

The band release a new concert film, documentary and album, Live From South Africa: Dust And Thunder, on February 3. It captures their first-ever performance in Pretoria, South Africa, in front of 50,000 ecstatic fans, and follows on from their Johannesburg EP, released last June, recorded in the eponymous city with Senegalese musician Baaba Maal, Cape Town band Beatenberg and Brit-Malawian trio The Very Best. A special documentary, We Wrote This Yesterday, is included with the special edition of the Blu Ray/DVD. It was filmed during sessions for Johannesburg, and sees the musicians collaborating.

Hot on the heels of the film's release, the band - Mumford along with Ted Dwane, Ben Lovett and Winston Marshall - have announced three headline shows in the US, will support U2 around Europe and the States as part of the Irish band's Joshua Tree anniversary celebrations, and will very shortly be heading into the studio to record what will be their fourth album.

"We feel really blessed that there are enough people in the world that want to hear us, so we have this vague responsibility to play to them," says Mumford, who was born in California but grew up in south-west London. "We do work hard, but we've got friends with real jobs, and they work a lot harder than we do. When we're on stage, we're as happy as we can be. So we want to keep making albums so we can keep justifying going on tour. There's no point sitting back when we're enjoying it so much, and we're all young and able to carry on at this pace."

He says the songs for album number four are currently only embryonic, but experiences in Johannesburg, and his own adventures with The New Basement Tapes - a Bob Dylan-themed collaboration with artists including Elvis Costello, My Morning Jacket's Jim James and Rhiannon Giddens of Carolina Chocolate Drops - could well see any new record being Mumford & Sons' most collaborative.

Mumford says the main aim for the future is to write songs so good that they can retire their biggest crowd-pleasers, Little Lion Man and The Cave, two songs guaranteed to turn even the most sedate of gigs into a hoedown.

"We were headlining festivals when we'd only released one album, so we really had to make that set work," he says. "Even with the second album, we were playing almost every song, so it was great with the third to have competition in the set, to be able to drop some of the older songs.

"It would be unthinkable to leave some of our songs off a set list, but that's the aim, to write better and better songs."

He doesn't think the band have worked out exactly what the next album should be, whether it will stray further from their roots, as they did with the stadium rock of Wilder Mind, or embrace them. "We need to think about what makes a Mumford & Sons record, what makes a record unique to us. We've been kicking about a few ideas, but we're yet to come up with any answers."

One thing Mumford knows is that he doesn't want to spend much more time watching footage of the band performing. The flip side of being in control of all their output, to a degree to which other bands would be envious, is that Mumford and co must approve everything. "It's just so awkward. I really don't like it. I'd just like to say I'm much thinner than I look on camera too!"

The concert captured in the film was the band's first show in South Africa. Despite the country being among the first to embrace the band's music, right back in 2009 when they released their first album Sigh No More, they took their time getting there.

From the crowd's reaction, it was worth the wait, and it seems the feeling was mutual.

"We should've gone there sooner, but we feel we made up for it," says Mumford. "It was one of the best shows we've ever played, and having it on film is the perfect representation of us on that tour."

Mumford & Sons released their live concert film and documentary, Live From South Africa: Dust And Thunder, on February 3. Visit www.mumfordandsons.com for more info