Travellers have set up camp on Tooting Common.
The group, who appeared today near Bedford Road, have been told to leave within 24 hours or face prosecution and having their vehicles towed away.
The common is visited by travellers each year however camping overnight on the common, without council permission, is a criminal offence.
Environment spokesman Councillor Jonathan Cook said: “Local people can rest assured that we are taking active steps to quickly remove this group from the common.
“By acting so speedily we have reduced the likelihood of this camp getting any bigger and also ensured that this group will depart before the common and its facilities run the risk of suffering any long-term damage."
The council has a designated traveller site in Trewint Street, Earlsfield.
Residents who witness any incident involving travellers on council-owned land are being urged to contact the town hall's emergency response team on 0208 871 6900. This is a 24 hour service.