The Met broke up an illegal rave under a derelict railway arch in Tower Hamlets on Saturday, slapping partygoers with £16,000 worth of fines.
Officers closed down the gathering after they were called to Tidworth Road E3 shortly after 1.30am on Saturday following calls from neighbours.
Around 10 people had initially illegally broken into the railway arch, using wooden crates to build an improvised bar area.
Numbers soon grew and it is estimated around 100 people attended the illegal rave.
When officers arrived dozens of the partygoers ran, many jumping over high walls into a neighbouring graveyard.
Officers detained 20 people who were each given a fixed penalty notice for £800.
Chief Inspector Pete Shaw, from the local policing command, said: “It is mad that people are still prepared to break the rules, despite the extreme loss of a life as a result of this virus. It is shameful some people are selfishly putting others at risk.
“With the roadmap announcement last week, we are all very excited at the prospect of returning to normal in June.
"However, events such as this risk undermining that roadmap and could cause further delays by creating a breeding ground for the virus. We will continue to do our part in shutting them down and taking action by issuing fines.”