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.

It has offered to restrict workers’ hours on the protected site to avoid disturbing otters in the early morning and late at night.

Construction work would last two years and involve the installation of a 30ft salmon ladder to enable the fish to swim upstream.