The scheme aimed to supply more than 5000 homes

There were more than 800 objections to the project, which involved sites around Sheildaig and Slattadale in Wester Ross.

It is the first time since devolution that the Scottish Executive has turned down a large green energy project.

Ministers said the landscape targeted for development was of national and international significance.

The plans involved constructing four new weirs, transferring water through a buried pipeline, building new turbine houses and other modifications to existing water courses and lochs in the area.

If successful, the project would have generated enough electricity to supply about 5,300 homes.

The executive's decision recognises the potential damage such developments can have on areas of outstanding natural heritage interest George Campbell RSPB Scotland

During the consultation period 848 people objected to the scheme, while only six people wrote in to offer support.

The applicant, Highland Light and Power Limited, was given an opportunity to respond to ministerial concerns at the end of last year.

But their reply did not satisfy ministers who decided that they had enough information to refuse the development without the need for a public inquiry.

Deputy Enterprise Minister Lewis Macdonald said: "We have a responsibility to balance renewable energy benefits with potential negative impacts on the environment and local communities.

"In this instance the potential impact of this scheme, now and in the future, on an area of national and international significance is simply too high and outweighs the potential benefits."

RSPB Scotland's George Campbell welcomed the executive's decision to refuse permission for the scheme.