Even before the coronavirus pandemic, British cities were already seeing a boom in underground raves.
But now, CNN reports British public health officials are alarmed by ongoing, illegal raves going on across the country.
Authorities have fresh concerns, much of them around the changing nature of drug use and the transmission of COVID-19.
Illegal raves are secretive, organized under the cover of private WhatsApp and Snapchat groups. Locations are revealed just as the party begins.
The lockdown raves aren't being run by established promoters, which means the events are uninsured and safety standards are unregulated.