Once in a while, a band comes along that doesn't just ignore the rule book, but rewrites it.

Formed in the late 90s, Kosheen have proved success doesn't have to be on someone else's terms. Fusing the plaintive, potent vocals of Sian Evans with the darkly intimate electronica of Darren Decoder and Markee Substance, Kosheen create songs where the sounds tell the story as much as the lyrics.

In 2003, their second stunning album, 'Kokopelli' took the fearless, emotive blueprint of the band's debut, 'Resist', and coupled it with Sian's more confident song writing, a heavier rock influence and the experience of live world-wide gigs.

With their new album 'Damage' due for release this year, Kosheen's place as one of the UK's most exciting, experimental live bands looks unshakable.

It all began years earlier when music changed the lives of all three band members. Darren Decoder - aka Darren Beale - played and wrote music in school punk bands in Weston-Super-Mare, recording their efforts and so developing an interest in production. When he went to university in 1989, though, he realised something was missing.

"I was getting bored of the sound of the guitar," he remembers. "I was putting it through so many effects and pedals that it wasn't even sounding like a guitar any more anyway."

His salvation came in the form of a young Geoff Barrow, future founder of Portishead.

"When I met Geoff, he introduced me more to the electronic side of music. What he showed me with samplers and stuff just blew me away!"

Spellbound, Darren sold his guitar, bought an Atari and a sampler and never looked back.

"That was the same time as the whole rave scene was going off. I loved Orbital and 808 State, so I started writing electronica and got a deal really early. Then I used to write hardcore stuff for raves and then did some really ambient drum n' bass like LTJ Bukem before I started Djing at raves and parties with Markee in Bristol."

Together, Darren and former Glaswegian indie kid Markee Substance created the seminal Ruffneck Ting club nights around Bristol and the South West. Raised on The Smiths, Echo and The Bunneymen and, later, Stone Roses and Happy Mondays, Markee was instrumental in the burgeoning drum n' bass scene.

The pair soon got to know Sian Evans. Brought up in a small South Wales town, Sian moved to Cardiff aged 16, squatting and sofa-hopping while working several jobs and travelling to parties and festivals. At the height of the rave scene, in 1991, she had a son, Yves, and reassessed her priorities. For the next four years, Sian and her son split their time between environmental protests and working at summer festivals. In 1996, they moved into a tepee on a travellers' site in Brechfa forest.

"I thought it looked a lovely way to live," she says. "I wanted to give him freedom to run around and have some amazing memories."

At night, after Yves went to bed, Sian wrote songs. Despite being brought up writing poetry and listening to Welsh folk music and Joni Mitchell, it was the first time Sian had wanted to create music.

"I used to keep diaries as a kid and turn them into poems. I've always found writing is better than talking sometimes. It's a way of getting things off my chest."

Realising her future lay with these songs (they formed tracks on Kosheen's debut album) she moved back to Bristol to find someone to play them with. Enter Darren and Markee.

"I was quite nervous to begin with. Until I was with Kosheen, I didn't think of myself as a songwriter. I knew I could sing but I didn't have a lot of faith in my writing. I just thought it was something I did for me. With Kosheen, I'd sing stuff to Markee and he'd say it was beautiful."

As a trio, they learned to combine their loves of rock, hip-hop, jazz, drum n' bass and folk and still create songs with a heart.

"I love songs!" Sian states simply. "Songs that start, have a middle, and end. You can put too much in a track. You can have a busy vocal, or you can have a busy track, but if you put two together it's just noise to me."

The world agreed they were special. Their compelling, anthemic track 'Hide U' reached number six in the UK, while 'Catch' hit number 15 and 'Hungry' reached 13. The album 'Resist', reached number eight in the UK and the top 30 in Australia, The Netherlands, Belgium and Greece. It has since sold half a million copies.

"I remember being in Vienna waiting to hear how our album had done," begins Sian. "The boys came into the dressing room and told me to guess the position. I said 15. It went in at number nine and I think I burst into tears!"

Fame brought further peculiarities. Their tracks popped up on Eastenders and Ronan Keating declared himself an avid fan.

"It wasn't an overnight thing," Markee explains, adding: "We've always said that if you put your heart into your music, if you're feeling it, then you've got a chance that someone else will feel it too."

Ignoring the accepted protocol that dictates 'dance' acts don't play live, Kosheen then set off on tour.

"I cut my teeth on pub gigs in Wales," Sian says, "so I really wanted to get the music of Kosheen represented live. The songs really translated because they're very melodic. A lot of them were written on the guitar and we can do most of them unplugged too. A lot of people are surprised when they go into the gig and see a full band set up. But no one's been disappointed."

Crowds of up to 17,000 have since seen the band play in Europe, Australia, South Africa, Asia and America. In 2001, Kosheen performed to a 20,000-strong crowd in Serbia, the first international band to do so since the trouble in the Balkans. Markee grins: "We didn't have a clue what to expect. And suddenly there were 20,000 people all singing 'Catch' back at us!"

While on tour, work began on their second album. Enthused by their live reception, they wrote tracks they knew would sound great on stage. The resulting 'Kokopelli' is a hypnotic, intimate collection of songs from the soul. Influences including The Pretenders, The Cure, Kate Bush and Radiohead all resonate.

After sell-out UK and European tours promoting 'Kokopelli', Kosheen have been back in the studio on their third album, 'Damage'.

It's a perfect amalgamation of the unique electronica elements of 'Resist' and the guitar-rock of 'Kokopelli' so they're rewriting their own rule book again.

Darren explains:"I don't ever want people to expect anything from us."