Prince Charles's aides said he had opposed wind farms for many years, and thought they should be built offshore - if at all. The prince was also reported as telling his staff that he did not want any links with events or groups that promoted onshore wind farms.

A friend of Prince Charles told the Sunday Telegraph: "This is a difficult issue for the prince because he is in favour of renewable energy and is concerned by the effects of global warming. But he believes that wind farms are 'a horrendous blot on the landscape'.

"He thinks that if they have to be built at all they should be constructed well out at sea."

A spokeswoman for the prince said: "The Prince of Wales has never made any public comment about wind farms."

Anti-wind farm campaigners expressed delight that they had apparent tacit Royal support.

Gillian Bishop, a spokeswoman for Views of Scotland, which opposes onshore wind farms, said:

"His Royal Highness is widely respected for his informed support of environmental issues, and is in a better position than most to withstand the jibes of those who regard all opposition to wind power as sacrilegious."

However, Friends of the Earth Scotland hit back by arguing that wind farms could enhance the landscape.

Dr Dan Barlow, its head of research, said: "The look and design of wind turbines has improved over the years. When sensitively sited, wind turbines can be beautiful and majestic. In some cases they have become tourist attractions."