Squatters last night moved into the former Norbury police station - and told officers they have no plans to leave.
About 15 trespassers broke into the disused London Road station, which the Metropolitan Police boarded up and put up for sale in September, at around 7.30pm.
Police officers called to the scene were powerless to remove the squatters, who told them they intended to remain until the force served an eviction notice.
Entering a non-residential property without permission is not generally a crime, meaning the Metropolitan Police would need to apply for a court order to remove the squatters unless other offences are committed.
The squatters are understood to remain the building this afternoon.
A spokesman for the force: "We can confirm that on Tuesday 18 March at approximately 8.41pm police received a report of squatters in a police building in London Road, Norbury.
"On police arrival, officers spoke to the occupants who have indicated they intend to remain at the location until served with an eviction notice.
"The local Safer Neighbourhoods team have been informed and will provide reassurance to the local community and regular patrols in the area."
The station was one of three closed and put up for sale by the Met last year.
South Norwood and Kenley police stations also shut in August under plans introduced by the under plans introduced by the London Mayor's Office for Policing and Crime.
- Riot damaged town benefiting from more than £23m investment
- Exclusive: X Factor star in 80s car wash action
- Add a Banksy or a Damien Hirst artwork to your shopping list when gallery opens for business
- VIDEO: 'Slippery tracks' disrupt trains across south London in aftermath of Hurricane Gonzalo
- Hurricane Gonzalo not expected to devastate south London and Surrey