A local charity has accused Conservative members of Brighton and Hove City Council of making a "nasty, politically motivated decision" about an advertising billboard.
Community Base, which runs a community building in central Brighton that houses 26 other charities, has had permission since 2004 to display adverts on the side of the building.
The billboard earns the charity about £20,000 a year, but permission was not renewed at a recent meeting of the council's planning committee.
Colin Chalmers, director of Community Base, said Tory councillors had complained about a recent Green Party advert on the billboard.
"Every other councillor supported us," he said. "But the Conservatives voted against us in unison.
"They didn't like the idea that we had allowed other political parties to advertise. This was a nasty, politically motivated decision that will cause real and unnecessary financial hardship."
A council spokeswoman said the advert did not meet planning rules because of its size and location on the main street outside Brighton station.