1 JUNE 05

Although I am completely confident that Tree House will eventually emerge, butterfly-like, from the ordered chaos of our Clapham building site, I have been feeling in need of a little eco-inspiration to see me through. So last week I joined a trip to a couple of eco-developments in the Midlands, courtesy of SPONGE, a network of eco-building professionals and enthusiasts based in South London (www.spongenet.org).

If the name seems curious, network members seek to emulate sponges in a variety of ways: sponges are actually a collection of individual organisms that work together for mutual benefit; they efficiently absorb stimulating nutrients; and they are good for a squeeze in the bath.

Our search for stimulation began in a Nottinghamshire field where lambs dutifully gambolled in the May sunshine. At the far end of the field the ground rose suddenly, climbing to a thin, gleaming line, the only visual evidence of the Hockerton Housing Project (www.hockerton.demon.co.uk).

Hockerton is an Arcadian vision of 'deep green' eco-living. At the other side of the mysterious bank, a long terrace of glass-fronted houses glittered in its earthen cloak, gazing across blossoming gardens to a lake where irises and bulrushes flourished. Washing hung in the bright conservatories, vegetable gardens sprawled up the hillside and ducks paddled across the lake, scattering the reflection of two slender wind turbines.

The design of the terrace is both simple and effective: a classic 'passive solar' approach that stores the sun's energy in heavy concrete walls and floors, creating a thermal fly-wheel across the year that keeps the indoor temperature remarkably stable and removes the need for central heating. In the winter, when the sun is low in the sky, the warming sun reaches deep into the backs of the houses, whereas in the summer the high sun pours into the conservatories but the deeper interiors remain shaded and cool.

Hockerton is a contemporary autonomous community. They generate their own energy, collect their own rainwater, process their own sewage (in a reed bed in the lake) and grow a lot of their own food. It didn't cost much to build and it’s clearly a delight to live there. If you and your mates want to build a fully-fledged rural eco-idyll, start here.

Happily, many of the ideas realised at Hockerton can be adopted in more traditional settings. Five years ago, a builder called Steff Wright visited Hockerton and was inspired to develop his own brand of eco-friendly executive housing. His company, Gusto Homes, has since flourished and won many awards for aiming well beyond the building regulations in environmental design (www.gustohomes.com).

We met Steff at Millenium Green, his successful development in the village where he lives. The houses do not look unusual but, like Hockerton, have south-facing sun spaces, high levels of insulation, controlled ventilation with heat recovery, solar hot water panels and rain-water harvesting systems.

If you buy a house at Hockerton, you have to be committed to the goals of a close-knit eco-community, whereas some of the buyers at Millenium Green admitted they couldn’t care less about green living - but were nonetheless pleased to find their hot water tanks filling up for free.

We could embark on a large scale conversion of fields to Hockerton clones as a sustainable solution to the housing crisis in the south-east. Although I would be all for it, consumer demand must be respected in such matters. So let's hope other developers follow Gusto's lead and build green houses for all comers, regardless of their interest in solar power and turnip growing.