A rave in Lincolnshire, East Anglia, ended in chaos at the weekend.
Riot police shut down a free party in Twyford Woods, near Bourne, resulting in 43 arrests and 21 injured officers.
Local news reports that 1000 people were in attendance, with 200 becoming involved in altercations with police.
The party was held to coincide with the UK Bank Holiday and Youtube titles suggest that the gathering was the 2015 edition of UK Tek, an annual rave that attracts heads from all over the country.
Police were called to the site following reports of loud music. Youtube footage shows them surrounding the rave, arresting aggressive revellers and seizing equipment such as generators. Film taken at night shows a police van being attacked.
Deputy Chief Constable Heather Roach said: "Illegal parties sometimes known as raves are just that, illegal. One of the core responsibilities and aims of the police is to make sure that people are safe. Gatherings such as this are not safe. There are no safety assessments or plans.
"Equipment to tackle fires or medical emergencies are generally non-existent. Crowd control measures such as barriers to prevent people being crushed or suffocated are not present and access to the sites for the emergency services such as the Ambulance Service or the Fire and Rescue Service are inadequate."
She also said the "incident" in the woods was a "disgrace". However, sending a troop of riot police into a rave on a Sunday morning is never going to end well.