FRENCH security officials voiced concerns today over a spate of mysterious and illegal flights by tiny drones over nuclear power stations.

The prime minister’s general secretariat for defence and national security (SGDSN) disclosed that authorities had counted about 15 drone flights over half a dozen nuclear sites since October 1. 

They insisted that France’s nuclear facilities were designed to withstand seismic and security risks, including those possibly posed by drones.

“Drone overflights are currently being carried out in a repeated and simultaneous manner over certain nuclear sites in our country,” said an SGDSN official.

“The objective apparently sought by this type of organised provocation is to disrupt the chain of surveillance and protection at these sites.”

Environment Minister Segolene Royal told French media at the weekend that investigators had no leads about who was behind the flights. 

A legal case is opened up for every suspected violation and those convicted could face fines of up to €75,000 (£58,600) and a year in prison.

Interior Minister Bernard Cazeneuve told French radio last week without elaboration that authorities had ways to neutralise drones. 

But his apparent confidence changed yesterday as he suggested that “the best way to be effective in this area is not to say what we’re doing.”

Greenpeace France has led sporadic, peaceful incursions into French nuclear facilities in recent years to expose security vulnerabilities, but the environmental group denies any connection to the drone flights.

France gets more than two-thirds of its electricity from nuclear generation — the highest proportion in the world.