Uh oh, just when it all looked to be going so well, Glastonbury was hit with a major deluge on Thursday night.

Shorts and sandals were swapped for waterproofs, hooded ponchos and wellies as rain bucketed on to the festival sites and the ground became trickier underfoot.

By this morning large mud slicks had appeared - although, unlike the worst years, there were still grassy areas which meant festivalgoers could find some cleaner spots away from the worst-hit paths.

The threat of rain - and the possibility of a further mudbath after two wash-outs in 2005 and 2007 - have been partly to blame for the sluggish sales of tickets this year. For the first time in a decade the festival failed to sell-out beforehand.

Asked why the event had been slower this time around, organiser Michael Eavis told Radio 4's today programme: "Three years of mud, don't you think? Wouldn't that put you off?"

Weather forecasts suggest - as is almost traditional at Glastonbury - there will be further rain on Friday, although it is expected to clear a little by Saturday.