The bust came after officers were called to Lambeth Road, Lambeth, where the event was taking place, at around 1am on Sunday.
After they forced entry into the premises, police from the South Area Command Unit with assistance from other agencies found 60 people inside the venue.
The team attempted to safely clear the surrounding area but were faced with a hostile crowd and several officers were assaulted, receiving minor injuries.
Two men, both in their 30s, were arrested in connection with the assault on the same day as the raid.
One of the man, 34, was arrested on suspicion of drunk and disorderly behaviour and taken to a south London police station. He was given a fixed penalty notice while in custody.
The other, aged 31, was arrested on suspicion of assault on an emergency worker and was charged and bailed to appear before Croydon Magistrates Court on Tuesday, 1 June.
Inspector Dave Laurie, Partnership & Prevention led for the Central South Command Unit, said: “Though restrictions are beginning to ease, this type of large gathering remains prohibited. Not only were those present taking unnecessary risks, they were also causing significant nuisance and disruption to the local area.
He added: "Officers should feel safe when going about their work on the frontline. The response they received is unacceptable. The behaviour of a minority will not be tolerated and we will continue to work in partnership with bodies like the council to keep our communities safe."