British tabloids have dubbed every party an "illegal rave" – but there have been three distinct types of event thrown over the summer months.
We spoke to organisers and punters about the importance of proper security at unlicensed events.
The Metropolitan Police recorded 133 unlicensed events in 2017.
The revelers deny the allegation, and police say there is no evidence they did it.
"I remember parties of ours where the police put their blue lights on for us to add to the lighting effects."
Nine police officers were injured when attempts to shut the party down descended into rioting.