The Dorchester Collection commissioned Purcell to design an eco-luxury spa within the grounds of their country house hotel. The brief required Purcell to design a standalone building with extensive facilities including treatment rooms, a heated indoor swimming pool, steam room, gym and restaurant. Purcell's ingenious design minimises the building's footprint within the Green Belt and makes the most of the magnificent views, without compromising on space or comfort. The two-storey spa building is partially submerged within the landscape, emerging from a living roof of chamomile, lavender and thyme. It is the world's first luxury spa to be built out of carbon negative lime hemp construction and also has a timber glulam monocoque structure. The project is 40% below its target emission rate and incorporates sustainable measures including a biomass boiler, a ground water heat transfer system and an ultraviolet swimming pool.