The Standon Calling music festival has been called off due to flooding.
The festival, which had been taking place in Hertfordshire, had a capacity of 15,000.
The Met Office had issued an amber warning for storms in the home counties on Sunday.
Eart Herts Police said in a statement: “Due to serious flooding, promoters of the @StandonCalling music festival have sadly cancelled this year’s event.
“We are working with the promoters to assist people with getting home safely or making other arrangements.”
Pictures of the festival on social media appeared to show large quantities of water and mud around the stages.
Standon Calling said on Twitter: “Unfortunately due to flooding we will no longer be able to proceed with the festival.
“If you can safely leave the site this evening please do so as soon as possible.
“We are working on getting everyone off site as safely and quickly as possible.”
The festival said it expected “considerable delays” leaving the site and warned festivalgoers not to drive if intoxicated.
Ticket holders can return on Monday to collect their belongings, the festival added.
Primal Scream, Craig David, De La Soul and Sophie Ellis-Bextor were among the acts scheduled to play on Sunday.