Home Secretary Priti Patel has signalled a crackdown on the organisers of large gatherings and illegal raves during a visit to the Metropolitan Police's central comms command centre in Lambeth.
The visit comes ahead of the introduction of tough new measures on Friday targeting those breaching coronavirus regulations.
Fines of up to £10,000 for those organising illegal raves in England will come into force ahead of the bank holiday, while participants at illegal events also face fines of £100.
Police have responded to a surge in unlicensed music events in recent weeks amid warm weather and an easing of lockdown restrictions.
"These are dangerous places and people should not be going along to them", the Home Secretary said.