The world's largest tidal energy farm could be built in British waters, it has been announced.

Two sites off Scotland and one off Northern Ireland are being looked at to house up to 60 underwater turbines generating 60 megawatts – enough to power 40, 000 homes. Blades would be ten metres below the surface to avoid ships. ScottishPower, the energy firm behind the plans, said the technology could make Scotland the global leader in the field.

Director of the firm's renewable arm Keith Anderson said: “This is a historic day for the development of marine energy. “The rapid technological advancement of tidal power has enabled us to progress plans for this substantial project which has the real potential to deliver significant environmental and economic benefits.”

The company is expected to apply for planning permission next year. ScottishPower insists there is no threat to marine life, but the Marine Conservation Society said it would want to look closely at the proposals and see a rigorous environmental impact assessment. The announcement came as the Crown Office opened parts of the seabed for leasing to developers.