The Queen’s attempt to improve the green credentials of Balmoral, her Scottish estate, has been stopped over concerns the plans are too noisy for red squirrels.
The Cairngorms National Park Authority, which is responsible for planning in the area, has called in a plan by the estate to create a new hydroelectric scheme.
It wants to build a turbine to generate power worth up to £650,000 a year from the River Muick, which runs through the property .
But objectors claim the project would be too noisy for wildlife in the area, including badgers, red squirrels and otters.
The decision is a setback for the estate, where the Queen spends her summer holidays .
Construction work would last two years and involve the installation of a 30ft salmon ladder to enable the fish to swim upstream.
A report by the authority said the proposal for a run of river hydro scheme raised issues of significance to the collective aims of the national park. It will now be held up while further investigations are carried out.
The scheme comprises the construction of a buried pipeline approximately 3km long, a semi-buried powerhouse and a pipe and channel returning water to the river.
The application, submitted by Richard Gledson, factor of the 55,000-acre estate, states: Balmoral Estates has already developed a hydro scheme on the Gelder Burn, which was commissioned in 2014.
Following on the success of this project, and with a view to increasing the economic and environmental sustainability of Balmoral Estates, a study was carried out in 2013 into the potential for additional hydro generation. Any surplus electricity could be sold to the national grid.
Last year, Prince Charles backed a UK Government initiative to sterilise grey squirrels in order to protect the native red squirrels. Balmoral also runs wildlife safaris, costing £60 per person, and lists the species regularly encountered as red squirrels, birds of prey, red deer, red grouse, black grouse, snow bunting and salmon.
Other green initiatives include a part-organic garden, overseen by the Prince, and solar panels on a cottage built by Queen Victoria for her servant John Brown.
A working estate, where deer stalking, grouse shooting, forestry and farming are carried out, its environmental policy states that it is committed to operating the estate in an environmentally sustainable manner.