THE four biggest metal acts in the world are playing a UK venue together for the first time ever next month – and we're giving away a pair of tickets worth almost £400 to see them.

Slayer, Anthrax and Megadeth take to the main stage at Sonisphere on Friday, July 8, and the mighty Metallica will be closing the first day of the 72-hour rock fest.

The Big Four, as they are known, are among more than 100 acts over five stages at the Hertfordshire venue, including Limp Bizkit, Slipknot, Biffy Clyro, House of Pain, Hayseed Dixie and the hilarious Richard Cheese with his band Lounge Against the Machine.

A host of comedians will also be on hand as an alternative to the music, with Sean Hughes, Jarred Christmas and Jackass favourite Steve O among them. Actor, musician and all-round funnyman Bill Bailey will also close the Saturn stage on the Sunday.

The event, now in its third year, is the biggest touring festival in Europe visiting no fewer than 12 venues across the continent in 2011, along with a huge variety of alternative entertainment, live DJs, discos and fairground rides.

And with around 60,000 people expected to turn up at Knebworth this year it looks set to be the most successful event yet.

If you haven't been lucky enough to get yourself a ticket this year we have two weekend camping passes, including arena entry for Friday, Saturday and Sunday, and a parking pass – worth a total of £360 – to give away.

All you have to do is answer the following question:

What is the name of Metallica's outspoken drummer?

This competition is now closed.

• Congratulations to Matthew Rose from Droitwich who correctly answered that Metallica's drummer is Lars Ulrich. Sonisphere will be in touch shortly to organise delivery of your prize!