Ticket sales for this year's Glastonbury Festival have proved as sluggish as the ubiquitous mud which has plagued the Somerset, south west England site in recent editions.

Organizers this morning (April 7) were still offering a "limited number" of tickets for entry to the famous June 27-29 fest, the biggest U.K. outdoor music event of the summer, despite tickets being released to the public Sunday morning.

In years past, Glastonbury's entire allocation of 137,500 tickets typically sold-out in a handful of hours. Only people who have registered can apply to buy tickets.

It's the first sign of a possible backlash against Glastonbury, which has been at the mercy of generally dreadful weather conditions in recent years.

In 2005, storms battered the site on the eve of the festival, turning the lush grounds into a mud-bath for the duration of the event. One particular camping site was flooded, ruining 400 tents and upturning portable toilets. Last year's version played out under dark skies and constant downpours.

Michael Eavis, a dairy farmer, founded Glastonbury on his farm in 1970. The first edition gathered a few thousand visitors at Worthy Farm; this year's festival has an authorized capacity for 177,500 people. Melvin Benn's London-based promoter Festival Republic handles licensing and security for Glastonbury. Festival Republic last year introduced the multitiered ticket registration initiative with online ticket agency SeeTickets, with an aim to force out scalpers and forgers.

Jay-Z, the Verve and Kings of Leon are tipped to play this year, although the line-up will not be confirmed until early June.