A drone fitted with video cameras will be flown over a British National Party gathering in Derbyshire after dozens of protesters were arrested last year.
Police are using the plane to monitor the event near Ripley on 15 and 16 August and any protesters who turn out. Last year police arrested more than 30 protesters near the site off Codner Denby Lane, but no-one was charged. Officers said it would cost "about £500,000" to police the event. The plane will be used to record evidence.
Chief Constable Mike Creedon said: "We will apply to the Home Office for special funding which is occasionally available. I'm not overly hopeful about this. Last year's costs were something in the region of £300,000. It will be significantly more this year. I would think we're pushing around half a million pounds, and that comes from a budget which is already heavily stretched."
In a statement Derbyshire police said that a pilotless drone plane would be used to record evidence at the Red, White and Blue festival. The force said: "The drone, fitted with CCTV cameras, will be used by a trained operator from the manufacturing company. It will record any incidents of disorder for evidence-gathering purposes."
It said it was not the first force in the country to use drone planes.