Campaigners have called for the Glyndebourne Opera House in East Sussex to abandon plans to build a wind turbine in its grounds.

The proposal to build the 230ft (70m) turbine at the world-famous site near Lewes was approved by the Government in July last year to much criticism from a consortium of environmental groups who said it would ruin the picturesque landscape.

Now the South Downs Environmental Protection Consortium has said data gathered by a wind mast which has been measuring wind speeds at the proposed site for the past year shows that the power likely to be generated by the turbine is a third less than predicted.

Ruth Chambers, of the Campaign for National Parks, said: "With the wind resource proven to be much lower than predicted, common sense should now prevail - the turbine should not be built and the stunning South Downs landscape should remain free of such industrial structures."

Officials at Glyndebourne - famous for its production of Mozart operas - said the turbine forms part of their vision to cut carbon emissions by 71% and make the venue more environmentally sustainable.

But Jacquetta Fewster, of the South Downs Society, said the venue should think of other ways to reduce its carbon emissions.

She said: "The landscape of the South Downs is far too precious to be blighted by an industrial-scale wind turbine.

"Now the data has shown the level of wind to be even lower than originally estimated, we again call on Glyndebourne to drop the turbine idea and look to other ways to reduce their carbon footprint."

Plans to build the 850kw turbine on a hill known as Mill Plain on the South Downs, which was recently given National Park status and is in a designated Area of Outstanding Natural Beauty, have attracted controversy since they were first announced in January last year.

Hundreds of people attended a public inquiry in February last year where Inspector Dr Andrew Pykett heard evidence from those for and against its construction, including wildlife broadcaster Sir David Attenborough who delivered a speech in praise of the plans.