The end is nigh. Orbital are bowing out this summer after 15 years leading the dance music revolution. Before they take the stage at Oxegen for their final performance on Irish soil, the Hartnoll brothers talk to Jim Carroll

All good things must come to an end and, for the brothers Hartnoll, this is where Orbital finally reach the end of the road and turn off the engines.

After 15 years of Chime and Satan, 15 years of playing live shows with miners' lamps on their heads, 15 years of shapeshifting exhilarating electronica, 15 years of the brothers working it out on bigger and better stages worldwide, Phil and Paul Hartnoll are taking a lap of honour before Orbital leave the building for good.

There's a final album (The Blue Album) and farewell shows in various countries before they say "sayonara" in Tokyo in August. The Hartnolls will then hug manfully and go their separate ways and the world will be left with just the albums and the memories of live shows past to remember one of the acts that helped make dance music much more than just a clutch of anonymous 12-inch singles.

As they face a final round of interviews, both believe the time is right for this long goodbye. "We're ready to move on and try something different," explains Paul. "We're doing this 15 years and I can feel that the cracks are beginning to show. We're getting into a creative rut because we're Orbital and people know what to expect. It gets stilted and unexciting so the best way to stretch your creative muscles is to stop the way you work, which means stopping doing Orbital."

They leave with their heads held high, their final album an affirmative, emphatic nod that Orbital were right. It's a Best Of without any Best Of tracks, a compilation of Orbital's stylistic highs. Phil believes The Blue Album turned out this way "because we decided to stop. There were all these loose ends that we didn't want to see going to waste, tracks that were too good to leave half-finished. It's stuff we'd intended for films which didn't get used, stuff for a jeans advert which didn't come to fruition, but we got great tracks out of it." In a way, Paul views it as their first album all over again: "First albums are always good because they're like a Best Of everything you've ever done, but this is a Best Of in the sense that it's the best of what's left." It could also be seen as a Best Of what's left of the class of the 1990s.

Along with Leftfield, Underworld, The Chemical Brothers and The Prodigy, Orbital were the ones who put a face on what was an anonymous pursuit involving DJs and white-label releases and watched the underground become the mainstream. After the rise and rise of dance culture came the fall, and it is to Orbital's credit that they leave the field with their reputation for innovation and creativity intact.

"I think we've had a good run," says Paul. "It's a constant turnover with bands and pop music, so to be finishing up after 15 years is a really long run. Seven albums means it wasn't a short-term thing or a flash in the pan. Seven albums is quite a catalogue to have on the shelf.

"It's a real achievement to be seen as a live electronic band who came out of that early rave era," notes Phil, "because it wasn't an era known for its live work. People remember the energy and exuberance of the live show. In our genre, it's quite unusual for a band to last so long, and especially for a band rather than a DJ to have so much impact. The stars were always the DJs, but an Orbital show was a good excuse for a lot of old ravers to go out and go a little crazy and have a bit of a blow-out."

Music will be all the poorer for the Hartnolls' departure because few dance acts mixed as many styles as they did. While Paul mentions Basement Jaxx as "the ones with the Saturday night Glastonbury vibe", you'd be hard-pressed to name another act who are as varied in their musical pokes as Orbital. Rather than just play either melodic atmospheric jangles or devilish evil breaks, they chose both. "When we started, there was always the temptation for bands to call themselves one thing if they were releasing an ambient track and something else again if they were releasing a drum and bass track. We always made a conscious decision to say 'look, we're Orbital, we like different stuff'. People used to get confused when we played Satan and Chime in the same set."

There are plenty of good times to remember to go with the hours spent waiting at airports. Paul views playing Glastonbury in 1994 as a particular highpoint, while Phil recalls a show in the Royal Albert Hall ("playing places where you were not supposed to play acid house is always good") and remixing Madonna and Kraftwerk. Even appearing on Top of the Pops to play Chime in 1990 sticks in their memory.

"You have to pinch yourself now and again," says Paul. "I honestly expected it to last for about a year, so there's always been a feeling that if it finishes now, fine, I've done more than I ever thought I would anyway. I think we've over-achieved in many ways so rather than pick just one point or gig or record, it's the whole thing, it has been quite overwhelming in some ways."

What comes after the final shows is time to spend doing those things that couldn't be done because of the day job. Phil intends taking up residence in any DJ booth that will have him and spending more time delving into recording studio technology.

For Paul, it's the lure of the big screen. "We've dabbled with film scores along the way but, more often than not, we've had to turn stuff down because Orbital was getting in the way. Now, I don't want to turn down film stuff, I want to go and do it. I'm not interesting in just getting a track in a film, I'd like to have a go at doing scores - but in my own time." The imminent arrival of twins, however, may curb his Danny Elfman tendencies for a spell.

At the moment, it's the final shows in London and on the festival trail that are uppermost in their minds. Bowing out at Glastonbury, T in the Park and Oxegen seems the most natural thing in the world to do, even if many are asking if they really mean "never again" when they say "never again".

"Of course, we don't know," says Paul. "We're about to do our last gigs and stop and do something different, so the last thing we want to think about is starting again."

"One part of you wants to say 'never say never', but another part wants to say 'never' because then it's final and you have that feeling of closure," says Phil. "It's beautiful to have finished the album and have decided to end this way and we're going to enjoy it."

They will close each show with Chime. "It started with Chime," says Paul, "and it ends with Chime to make one big Orbital loop from start to finish. I think that makes sense."

The Blue Album is out now. Orbital play the Green Room at Oxegen on Saturday, July 10th