ORGANISERS want to extend the Sonisphere Festival at Knebworth Park to three days. Although gates opened to the campsite for early arrivals on Thursday this year, the music didn't start until lunchtime Saturday. Download at Donington Park in Derby and the

ORGANISERS want to extend the Sonisphere Festival at Knebworth Park to three days.

Although gates opened to the campsite for early arrivals on Thursday this year, the music didn't start until lunchtime Saturday.

Download at Donington Park in Derby and the Reading and Leeds Festivals are already three-day music events.

Linkin Park and Metallica headlined the first Sonisphere in the UK earlier this month and next year's festival will remain two days in length.

But after the success of this year's inaugural rock and metal spectacular at Knebworth, Sonisphere creator Stuart Galbraith confirmed that the festival will eventually expand to match its main rivals.

"The ambition with Sonisphere is to grow it organically," said Galbraith.

"There's no point having one big year where we are lucky enough to get three big headliners and then to struggle to find three solidly good days for future years.

"So I think once we've got a couple of years under our belts at two days, then yes we will look at adding a third day - but only when it's ready.

"We don't want to force the growth."

This year's music fest attracted a total attendance of around 80,000 rock fans, with in the region of 35,000 turning up on the first day for Linkin Park and 45,000 for metal gods Metallica on the Sunday.

Other bands that played over the weekend included Nine Inch Nails, Heaven & Hell, Machine Head, Limp Bizkit, Feeder, Avenged Sevenfold, Bullet for My Valentine, Anthrax, Thunder and Alice in Chains.

Looking ahead to next summer's headliners, Galbraith added: "We've got some ideas.

"We're looking to build a volume together that we can announce in one go.

"I very much doubt that will be prior to Christmas; probably Christmas to early January there will be an announcement."

The exact dates for Sonisphere 2010 have yet to be confirmed, but the festival will take place around late July to early August time.