Councillors have refused to grant retrospective planning permission for a controversial police radio mast.
The mast, at Treworval Farm in Mawnan Smith, was put up in November by MM02 on behalf of Devon and Cornwall Police.
Kerrier District Council unanimously rejected the application on Tuesday and said it wanted the Tetra mast switched off "with immediate effect".
Police say the masts are needed to improve the coverage of their radio network and speed up response times.
Officers at Kerrier District Council had recommended that councillors, who had previously thrown out three applications for Tetra masts, give it conditional approval.
The masts have prompted protests from some people at several sites in Devon and Cornwall who claim there has not been enough research into possible health risks.
Last month, the Mawnan Smith mast was attacked by vandals.
County councillors last week agreed to ask the Home Office to intervene to prevent the masts being switched on.