Millionaire plans to replace stately home with zero-carbon showpiece

It will also be one of the country's most environmentally friendly buildings, a real zero-carbon home for the 21st century.

Mr Milne has already put up Scotland's first commercially viable carbon-neutral show home. Now he is determined to lead the eco-building movement from his own front door in Bieldside, outside Aberdeen.

First, however, he must get planning permission to knock down his existing family property, a rambling mansion that was once the home of Princess Diana's grandmother.

Yesterday he said: "After extensive investigations, we reached the conclusion that the best solution for us, and for the area, was to replace the existing property with a new house.

"This gives us the opportunity to create an elegant, classically-styled country pro-perty using modern methods of construction and the latest renewable technologies, such as ground source heating and grey water technology.

"Our aim is to build a stunning, low-to-neutral-carbon house that complements the surroundings, offers our family an attractive living environment that meets our needs and creates a building of which we and the region can be proud for generations to come."

Zero-carbon homes are far from an eco-friendly fad for the rich and famous. Private homes account for a little less than a third of all greenhouse gases. Scotland's homes, thanks to a combination of poor insulation and dampness, are stunningly inefficient. Private houses, for example, still account for six times as much carbon emissions as aircraft.

Chancellor Gordon Brown last year unveiled plans to make all new-build homes carbon-friendly in England and Wales within a decade. Scotland will follow suit, opening a substantial market for the kind of home Mr Milne envisages for himself and, more importantly, for his tens of thousands of clients.

Mr Milne - whose fortune has been measured at just under £300m and who owns a substantial share of his beloved Aberdeen Football Club - has lived at Dalhebity House, Bieldside, with his partner, Joanna, and their two children since 1981.

The sprawling property, however, has a far longer history. Once a magnificent granite mansion, it was the stately home and birthplace of Ruth Sylvia Gill, mother of Frances Shand Kydd, Princess Diana's late mother.

Miss Gill lived in the magnificent granite mansion with her mother, also Ruth, and father, Colonel William Smith Gill, a Scottish landowner, until she married the wealthy Edmund Burke Roche and became Baroness Fermoy, who become a confidante of the Queen Mother. This was the link that brought the Spencers into intimate contact with the royal family.

Mr Milne, who chairs Aberdeen FC, said he had been working with leading designers and architects to ensure that the property was aesthetically and environmentally pleasing.

He hopes to build a period-style "Victorian" property using natural stone, slate and timber to blend in suitably with the area, an upmarket area of established homes that boasts some of the most prestigious addresses in the UK.

Jim Brookman, of the interior design firm Brookmans, said the plans paved the way for a "magnificent" property with impressive scenery.

He said: "We have taken inspiration from the classic Scottish baronial styling of the past to create a truly elegant, stately home that will rival some of the most impressive properties in the south of England in terms of stature, grace and beauty."

Mr Brookman said the grounds would play an important role in the plans, with formal gardens blending into softer landscapes and merging into the nearby woodland areas.

Experts have long argued Scots must reduce the amount of energy spent heating their homes, not least to tackle fuel poverty and global warming.

Most suggest improved roof insulation, especially for new houses. But some cast doubts on environmental justification for wholesale demolition and rebuilding, stressing that the work itself is carbon-intensive.