Bellowhead, an 11-piece band that plays traditional folk-dance tunes, sea shanties and folk songs. They have a four-piece brass section. And a four-piece string section. Their first album, Burlesque, featured material from the American minstrel movement, the Napoleonic Wars and sea shanties from Brazil. Surely, that would never work?

Well, work it did, and now that the band are bowing out, there are a lot of annoyed people, according to founder member John Spiers, whose main instrument is the melodeon, and is known in his local Oxford circles as Squeezy. "A lot of people are very cross with us, I have to say," he says sincerely. "The people who have supported us on this journey at different stages are some of the most dedicated fans. Lunatics even," he laughs. "Some of them are coming to their 50th gig or something… We know them well enough to call them by their names. It looks like such a big thing but it also feels like quite a small thing sometimes."

From the outside they are big. As well as being an 11-piece, their third album, Hedonism, became the biggest selling independently released album of all time, while their last album, Revival, was released on the iconic Island label, and made number 12 in the charts, their highest ever. They've been featured in both The Simpsons and The Archers, and their last tour sold out well in advance, as has this, their 'farewell' tour, including a final date at the place where it started, Oxford Town Hall, on 1 May. "It's difficult," says John. "It feels like it's going to be harder than I thought it was going to be, as the time approaches, and you start looking over the music. It normally feels like an on-going process, but it does feel like it's really final," he laughs. "It's quite unexpected, all the emotions, about not doing this again. On the last tour (the first part of their 'Farewell Tour') it seemed to be a lot more emotional for the audience, as we played each place for the final time. The last gig will be quite different."

The seeds of Bellowhead are perhaps reason enough for them to have been loved and admired by so many. Sitting in a traffic jam one day, Spiers and Jon Boden were drawing up a list of musicians they thought might be good for a big band project, that was in the draft stages. They'd been playing together as a duo since 1999, releasing albums, winning the Best Duo category at the BBC 2 Folk Awards in 2004, and joining Eliza Carthy's band, touring around the world. As fate would have it though, "Our plan at the time was the creation of the Spiers & Boden Big Band. We were helping promote the Oxford Folk Festival for Tim Healey (Dennis Healey's son) in Oxford Town Hall, and he basically came up to us and said, 'look guys, I've been wracking my brains. I want to headline with an English band. Who can I book'? And I said, 'book us!' We'll do it'! So we kind of put the pressure on ourselves. We already had this idea of the Spiers & Boden Big Band, and now we were forced into a deadline."

So, the calls were made and the first rehearsal booked. "We had to do a photoshoot before we even did our first rehearsal, so that there was a picture of us in the programme! "laughs John. Along with Benji Kirkpatrick, Rachel McShane, Paul Sartin, Pete Flood, Brendan Kelly, Justin Thurgur, Giles Lewin and Andy Mellon, the band came together with little idea of what to expect. "We played through the arrangements that Jon had written while on a Eliza Carthy tour in Australia; the scores for everyone to play. Some of them sounded good, some of them less good. Nobody could really see what was going on. But we played all day and got through the rehearsal and went to the pub in the evening. The first actual performance we did was a wedding ceilidh in a barn in South Oxfordshire. It was a great success. The next day, the gig happened. It was incredibly nerve wracking. There was a big audience and a lot of expectations. I've got a recording of that gig and it was dreadful. But the people who were there saw some promise. But by our standards some of it was shocking!" he laughs again.

Spiers & Boden's second album had been called Bellow, and with a nod to fellow Oxfordians Radiohead, they named the band Bellowhead. They've been a remarkably consistent outfit ever since. Originally a ten-piece, they soon recruited member number 11 (Gideon Juckes), and only twice have they shed members; Lewin and Juckes, to be replaced by Sam Sweeney and Ed Neuhauser, the present line up being the same since 2010.

"The aim", says John, was to make "English world music", which is how they styled themselves via their independently released début, the E.P.Onymous. "Folk music in general wasn't getting a huge amount of media attention, but world music was. “What's different with our music? It can be modernised, brought up to date. How's about it, music industry?”

How would you describe what you do? "If I was to describe it to someone who hasn't heard it before, I think I would say it's based around the traditional music of the British Isles primarily. That's the source material we take. All we do is play with the music, explore it, and each track will have a different feel to it. One track may have an afrobeat, african feel to it, because that was something the person writing her music was playing around with at the time. Other things are almost full on disco, and others are incredibly orchestral. When we go from telling a sea shanty to playing a dance tune for the crowd to dance to, we'll adapt what musical knowledge we all have to apply to that source material, so it ends up sounding like a train crash of styles. But because we have been playing together so long it kind of works.

"Every step of the way its gone beyond what we were aiming for," says John. All we were hoping for was to put together a band, made up of all the disparate musicians on the folk scene – although some of the players weren't on the folk scene then – and we saw that there was that thirst to book us. People were contacting us in their droves. We sent Ian Anderson of folkroots magazine a demo, with the specific instruction not to review it because it was a demo made to get gigs. He was at that first gig, and he instantly reviewed it. We couldn't escape it then, everyone wanted to book us. Thereafter, we started playing pretty mainstream festivals and getting played on Radio 2, and not just on the folk show. We never aimed for that. It was never part of the remit. But, the release of Hedonism saw that happen."

For the final tour, they've released a CD/DVD, documenting their previous 'final' tour. It's their first ever live album. "It was something people said we should do; we're always touted as a live band. As the tracks were being mixed and sent through to us, I was thinking 'why didn't we do this before. They sound amazing'! We recorded almost every gig to make sure we got a good take of everything. There's a couple on there which we had never released before, and a new track, ‘The March Pass’.

Their remarkable story, however, is shortly to come to an end, as Bellowhead play their final gig at the place where it all really started, Oxford Town Hall, and on a day (May Day) that is very significant for folkies in general, it being International Workers Day. So, why call it a day when things are going so well? "The main driver behind disbanding was Jon (Boden). He said he didn't want to carry on with the band after this tour. There was no reason why we couldn't carry on. We can play the instrumental stuff, but to find another singer, for someone else to come in and sing those songs, it would have been a very strange thing. Given how long it takes for everything this band does, it was slightly too daunting a task.

"If we were all earning our livings from this band in its entirety and doing very well, we might have carried on. But the fact of the matter is that we're a huge sprawling band, so that any money that is earned is spread very thinly. It's not a great earner even with huge live shows. The state of the music industry means you can't make much from recorded music unless you sell millions of copies. We weren't prepared to take that risk of going back and starting again with someone new.

"None of us are writing off playing together completely. But if we want to tour we have to start collating diaries two years before that. So, if it does happen, it might be quite a while before it gets going," he laughs.

Music will remain very much central to Spiers life, as he looks forward to releasing a solo album, while all the other band members are involved in countless other projects, as they always have been, in conjunction with their Bellowhead duties. But, back in 2004, folk was still a bit of a dirty word and a little bit uncool. Now, it's practically mainstream. "I'm proud for helping to make folk cool. And I’m really proud of how we’ve taken the English folk tradition and made it acceptable to people who would have never given it a second look."
Jeff Hemmings

Website: bellowhead.co.uk
Facebook: facebook.com/bellowhead
Twitter: twitter.com/bellowhead