Tickets are being offered at more than four times their face value

A pair of tickets for the three-day event, one of the highlights of the summer's music calendar, should retail for �210.

But internet auctioneer eBay is advertising passes for the weekend-long festival for as much as �980 a pair.

Festival founder Michael Eavis has condemned the sales and says he will cancel any such tickets.

He said: "We have been told about a number of tickets being sold on e-bay for �500 each, which is worrying.

Those tickets will not be issued - the people will not be able to sell them Michael Eavis

"If the tickets are on for �500 a day after selling out, imagine what they will go up to in two weeks.

"What we have decided is to cancel those tickets - they will not be issued, so the people will not be able to sell them."

Mr Eavis added: "We are pleased to have sold out in a way, but also sad, because it means people who have been coming to the festival for many years have not been able to get tickets.

The huge mark-ups on tickets have been criticised by festival fans, many of whom have used the Glastonbury website's messageboard to make their feelings known.

A spokeswoman for eBay said: "eBay views the selling of these concert tickets as a private matter between the event organiser and the seller.

"eBay has over 62 million users and over 15 million items listed for sale on our sites at any one time.

"We do not review listings provided by users and we are not involved in the transactions between buyers and sellers."