A campsite adjacent to the car park was evacuated after a fire raged through the car park and destroyed 80 vehicles.
There were no reports of anyone being hurt
The festival, which is being headlined this year by Madness and Damien Marley among others, hosts around 50,000 people and is taking place in Hampshire this weekend.
At around 4.15pm yesterday, firefighters responded to a report that a fire had taken hold in the car park. Up to 80 cars were destroyed and the campsite was evacuated.
‘Multiagency response to estimated 80 vehicles destroyed by Boomtown fire,’ said the South Central Ambulance Services Hazardous Area Response Team.