At £3,000 per sq ft, it is thought to be a world record for a country home.

Orchid House designed by the award-winning architect Sarah Featherstone, is situated in the 550-acre Lower Mill nature reserve near Cirencester, which was created from abandoned gravel workings. The development is one-fifth housing and four-fifths reserve.

The house, whose design is based on the bee orchid found on the reserve, was sold off-plan last week to an anonymous buyer.

The house will take three years to build and hopes to produce more energy than it uses with an underground heat pump, geothermal heating and cooling, rainwater and solar and wind power.

The development is the first practical articulation of the vision of Jeremy Paxton, an environmentalist who launched the Landmark Houses Programme in 2005.

Mr Paxton plans 15 individual houses built on the estate by top architects including Will Alsop, Richard Meier, and Pierre d'Avoine.

Construction is due to begin in September.