Extra Sonisphere Festival 2011 day tickets available
Organisers increase capacity at Knebworth
Theo Tritsarolis on 13 June 2011
While the capacity itself has increased, the campsite's space restrictions prohibit extra weekend and camping tickets
from becoming available, so only an extra allocation of single day tickets are on sale now.
They are priced at £80 (plus booking fee).
Festival chiefs have also said that weekend camping tickets are nearly sold-out and those wishing to go advised to secure their tickets quickly.
Click here to buy Sonisphere Festival tickets.
The festival's stellar line-up of rock and metal includes, for the first time in the UK, the Big Four – Metallica, Slayer, Megadeth, and Anthrax.
Other notable appearances will come from Slipknot, Biffy Clyro, Weezer, Limp Bizkit, Opeth and many more.
Click here to see the full Sonisphere Festival line up.
Those wishing to take a break from head-banging and moshing can stay entertained by comedy acts such as Bill Bailey, Steve-O, Sean Hughes, Howard Marks, Brendon Burns and Andrew Maxwell.