Police have used CS spray on protesters during a demonstration against gentrification in Brixton.
Scotland Yard confirmed the spray was used after members of Reclaim Brixton entered the local police station.
A man was also arrested on suspicion of criminal damage after estate agent Foxtons in Brixton Road had a window smashed and graffiti sprayed on it.
Reclaim Brixton said it was in a "fight against gentrification" which it said was "killing" the area of south London.
On its Facebook page, the group said: "Today vibrancy is sold to garnish property development posters and overpriced bar branding, but in doing so, it is also slowly being killed.
"Social diversity is driven out by lack of truly affordable housing. Local businesses are driven out by increasing rents and redevelopment schemes that benefit national and multinational businesses, siphoning money out of the area.
"Local spaces for people to meet, celebrate, get support or education are being decimated. Brixton's vibrancy now has a question mark on it."
Scotland Yard said during the planned event it had also removed protestors who had gained access to Brixton Town Hall and officers were "monitoring" the situation.