Queen were due to perform with American idol singer Adam Lambert

Rock festival Sonisphere has been cancelled, organisers have confirmed.

A web statement said they had fought hard to keep it going but that "a very challenging year" meant the event wouldn't have satisfied fans and the artists.

The event was to take place at Knebworth Park, Stevenage on 6-8 July.

Adam Lambert was due to headline on Saturday with members of Queen. Ticket holders will receive a full refund direct from their ticket agent.

The Sonisphere statement said: "We also want to send a huge thanks to the Sonisphere fans who stuck by us and we are so sorry that we can't fulfil what we set out to do."

Organisers said the cancellation came with "very heavy hearts and much regret".

Evanescence, Marilyn Manson, Cypress Hill, The Blackout and Faith No More were also on the line-up.

Other acts who were due to perform included The Darkness, Incubus, Refused, Ghost, Flogging Molly and musical comedian Tim Minchin.

On Wednesday, Queenonline.com published news of the cancellation but the information wasn't confirmed until today.