What one of the local papers said...
"Rock fans suffer hypothermia
Dozens of music fans were treated for hypothermia at the midsummer pop festival at Knebworth at Saturday.
Emergency services had to work through the night as wintry conditions caused havoc at the all-day event attended by 70,000 people.
Inches of rain fell, turning the arena and car parks into a mud bath and keeping 12 ambulance crews at full stretch caring for casualties of the weather.
Six tractors loaned by nearby farmers were put into action to drag bogged-down coaches from the fields used as parking areas.
In all about 300 spectators were treated for various injuries and the effects of the cold.
Ten people were taken to the Lister Hospital in Stevenage, mainly suffering from the effects of alcohol, or from burns received from one of the fires lit in the bid to keep warm.
Police made 12 arrests in the surrounding area with only one of those arising from an assault made in the park."
Thanks to Garry Smith