ONE of the main stage bands set for this summer's inaugural Sonisphere Festival at Knebworth House have pulled out of the rock event. American metal group

ONE of the main stage bands set for this summer's inaugural Sonisphere Festival at Knebworth House have pulled out.

Fear Factory have cancelled their appearance as support for Linkin Park on the first day at Knebworth on August 1.

The American heavy metal group, who were reuniting for their UK return at Sonisphere, cite recording commitments for their decision to scrap all forthcoming European dates.

No replacement has been announced yet.

A statement from festival organisers said: "Fear Factory have sadly had to pull out of all of their summer gigs, including Sonishphere's UK date at Knebworth.

"In a statement from Burton C Bell and Dino Cazares, they apologise saying that they are postponing the dates to concentrate on finalising and the writing and recording of their new album."

Fear Factory are the third main stage act to pull out of Sonisphere.

The Sword are no longer playing on the Metallica day, August 2, while Frank Turner has decided to play the Reading and Leeds festival instead of the Hertfordshire stately home.

There are also now doubts about Saturday sub-headliners Heaven & Hell, the group comprising members of Black Sabbath.

They couldn't play in Spain on Sunday night due to guitarist and metal legend Tony Iommi being unable to perform.

The first European leg of Sonisphere fronted by Metallica took place in Holland over the weekend.

The touring festival arrives at Knebworth on August 1-2 with the likes of Nine Inch Nails, Anthrax, Feeder, Alice In Chains, Coheed and Cambria, Bullet for My Valentine and Avenged Sevenfold joining headliners Linkin Park and rock gods Metallica.