It's a good occasion to disconnect from technology, go off the grid and enjoy a few days of carefree excitement. Or not. 

Along with booze, music and mud — a lot of mud — British festivals may have another feature: mass surveillance. 

Last year, Leicestershire police scanned the faces of 90,000 festival-goers at Download Festival, checking them against a list of wanted criminals across the country. It was the first time anywhere in the UK that facial recognition technology — NeoFace — was used at a public outdoor event.

Privacy campaigners — and Muse frontman Matt Bellamy — expressed their fury at authorities after they casually mentioned the use of the surveillance project on Police Oracle,a police news and information website. Police didn't use any other method to warn festival-goers about the controversial initiative.