A derelict stable yard’s transformation into one of Britain’s most energy efficient visitor attractions has drawn fresh praise in the form of an ‘excellent’ environmental award.

Morden Hall Park received the accolade from BREEAM, a globally recognised environmental rating system, after nearly £1m of lottery funding went into the renovations, completed in 2011.

In November 2012 the park, run by the National Trust, also completed the installation of an Archimedes Screw hydroelectric turbine, which can generate enough power for 16 households for a year.

Andrew Harris, the National Trust Building Surveyor for the project said:: “This has been such an exceptional project and one that I have been so very proud to have been involved in.

“The BREEAM ‘Excellent’ award is a fitting conclusion to all the planning and hard work which went into both the design and construction of the stable yard’s renovation”.

The restored stable buildings use three different types of solar panels, with one designed to blend in with the original roof tiles, an air source heat pump, a wood burning stove and under-floor heating.

Giant rainwater harvesting tanks beneath the ground collect water to flush the toilets and recycled and natural materials are used wherever possible.

Councillor Andrew Judge, Merton Council's cabinet member for environmental sustainability and regeneration, said of the ‘Excellent’ rating: “This is a huge achievement for a historic building.

“The sensitive refurbishment of the stable yard means that it has exceeded the standards required by the council for new build properties – and it’s much easier to use modern energy-efficient technologies in new-builds than in heritage buildings”.