The spread of wind farms means that man-made development can be seen from 70% of Scotland.

The latest survey by Scottish Natural Heritage (SNH) into built developments shows a rise of 1% from the previous year.

The latest report, based on data from 2010, singles out wind turbines as the principal type of development behind the increase.

Turbines were visible from 35.6% of the country in 2010 as opposed to 31.6% in 2009 and 19.9% in 2008.

All of the other components of development showed either no change or a change of less than 1%.

Ian Jardine, SNH chief executive, said: "The purpose of this report is to reveal the changes affecting Scotland's landscape as a result of built development. This is perhaps unsurprising given the importance of the renewable energy sector in Scotland."

The Scottish Government is already proposing restricting or banning wind turbines in up to one-third of the land mass, but Dave Morris, director of Ramblers Scotland, said ministers had to take into account SNH's most recent findings on visual impact.

He said: "This should be sufficient to persuade the Scottish Government that in areas where turbines are permitted they should be reduced in height and the maximum height to the tip of the blade should be 30 metres. If there has to be higher turbines, they should be around docklands or oil refineries where there is already considerable visual vertical intrusion from chimneys and cranes."