London (Agencies): India's steel magnate Lakshmi Mittal decides to construct a 30 million pound mansion on the outskirts of London that designers claim will have a "zero-carbon" footprint once it is completed.

Mittal, the 60-year-old Britain's richest man wants to build a country home in the Surrey green belt that is self-sufficient in energy and harnesses outdoor temperature variations to create natural air-conditioning, The Sunday Times reported.

The unique latest design will not only ensure the house is zero carbon, but will make the entire 340-acre estate carbon negative.

The project is Mittal's first country home. His main home is in Kensington Palace Gardens, west London, a house bought from Bernie Ecclestone, the Formula One mogul, for 57 million pounds and decorated with marble from the same mine that supplied the Taj Mahal.

Mittal refused to comment on the Surrey Hills project, but a statement issued on his behalf by the planners said, "Reinstatement of a substantial country mansion on a grand scale is considered to present the best means of securing the long-term future of Alderbrook Park as a single, well-managed and high-quality estate."

Mittal bought the land through an offshore holding firm, which disguised the identity of the buyer. His name leaked out because correspondence between his wife, Usha, and the Royal Parks was included in the planning documents.

The house will be constructed on a stone plinth, which will provide various terraces on which to enjoy the cocktail hour.

It will have about 10 bedrooms, outdoor and indoor swimming pools, a fitness centre, an under-ground art gallery, tennis courts, sculpture garden, an arboretum and croquet lawn.

Mittals will grow sufficient wood on the 340-acre estate to feed giant biomass fuel boilers to provide heating and hot water. Estate workers will chop down 100 tonnes of wood a year for the boilers and plant trees to replace them.

Solar panels on two huge roofs will turn sunlight into electricity. Underneath each roof will be a courtyard, which will act as a "lung" for the surrounding rooms.

In the summer, natural cool air from the estate's wooded places will be drawn into the courtyards by underground stainless steel tubes. In the winter, solar-heated air will be drawn down from the roofs.

Although the site lies in a designated area of exceptional natural beauty near Cranleigh, Mittal hopes to win permission for its construction through a special "knockdown" deal, the report said.