From the street - and remember that postwar suburban villas were designed to be viewed from the kerb - all you will see is a fence marking its perimeters, and a ramp disappearing downhill a few feet from the pavement. From a passing Jumbo jet the U-shaped house, 17 metres by 8 metres, will be appear with a car glinting on one arm, and a 17-metre strip of meadow grass on the other, with the fence connecting the two.
Underneath this will be three zones for living, cooking and eating, and sleeping, with a small service-area for washing and bathing. Light will flood in through the windows around the sunken courtyard which will be open to the sky. Carefully sited for privacy on its small plot, no one will be able to overlook what Pierre d'Avoigne describes as "an atrium underground".
At pounds 140,000 to construct, the house is not exactly a bargain basement. Modern methods of construction more like open-cast mining will be used to sink the steel frame on piles into the ground with as little impact as possible. The frame will be up in six weeks, and then the kitting-out and cladding begins. There will no glint of its steel once the house is clad outside in polycarbonate the colour of brown heather to prevent damp, and lined with plywood within.
The world's first steel-frame underground house may be discreet, but its impact on suburbia has been profound. Those who think that living in the suburbs is the pits may be astonished that Pierre d'Avoigne took them literally. Not surprisingly, a potentially fatal attack of Nimby- ism broke out in the surrounding area. "Tens of people - at least 40 - signed a petition, but I understand their concerns," he says. " It will be noisy and disruptive, though I have tried to minimise building time and noise with the contractors. I've been very open with them."
At first, Ealing Council refused planning permission. "Over-developed, out of character and sub-standard accommodation," they claimed. But on appeal the inspector overturned the "out of character" reference, and denied that the blueprint would provide sub-standard accommodation. The stumbling block was the height of the living space, which was planned to stand about three feet above the pavement with its flat roof sown with meadow grass. Neighbours feared the d'Avoignes would be able to overlook them from their green roof terrace. Their objections were upheld, but the inspector's report showed the architect the way forward by lowering the roof back to ground level and introducing a double-height chamber below ground. Planning permission was then granted.
This invisible house marks a turning point in the architectural perception of the suburbs. Most contemporary architects see working in them as a cul de sac rather than a smart career move. You won't catch any of the fashionable ones living in "Mon Repos" at Carshalton Beeches. Alpine gardens, double garages with up-and-over doors, Tudor spillikins tacked on above bolt-on Georgian bays, picture windows and portholes are not the stuff of modern architecture.
Since the suburbs depend upon private transport to reach them, it is hardly surprising that they are dominated by the car, and Acton residents have mostly cemented over their front gardens to park their vehicles. Pierre d'Avoigne taps into that typology with his own car parked below ground on top of his house. He is quite at home in suburbia. Reminding us that David Bowie first fell to earth in Streatham and that The Who sprang out of Acton, he believes that "suburbia is a hot bed for subversive ideas".
For example, at the Ideal Home exhibition earlier this year, he radically redesigned terraced housing by planning a row of terraces laid flat on their backs horizontally, rather than up in the air. Alas, this lateral thinking for the Concept House ended up in Olympia not as he had designed the winning entry - in a row of five with their flat roofs grassed over into communal gardens - but as a single unit without access to the roof. It still caught the eye of the innovative Urban Splash, who want to build terraced housing in Hulme, Manchester, as well as for two housing associations in York and Shepherd's Bush, west London.
Another housing design competition entry by D'Avoigne architects for the House of the Future, to be built at St Fagan's museum of Welsh life, looked as if it had stood on its site for ever - which is perhaps why it didn't win. But in its pitched slate roofs were photovoltaic cells to store sunlight for energy. Walls were constructed as timber frame and insulated with recycled newsprint, then clad in blue-black slate. Internal walls were to be made from plasma screens or beams of laser light, since the frame method of construction allows anything to happen.
His competition document explains that "vernacular buildings are ones in which space planes are generic and general purpose, and the grammar of construction economical and prudent while the specifics of material style and finish are left to the builder and dweller. As a rule, this is completely misunderstood by the volume house-building companies of today, which manufacture various vernacular styles with great emphasis placed on elaborate subdivisions of rooms internally according to specific functions."
D'Avoigne, whose French father and Indian mother sent him to school in Bombay, spent five years at the Birmingham School of Architecture in the seventies at what he describes as "the tail end of the modern movement". Much influenced by Mies van der Rohe and Le Corbusier, he proudly describes himself as modernist because he still has the social agenda of designing housing.
A heightened social awareness in the postwar era gave modern architects the sense of a broad social mission. Socialism in its multiple forms was not just a background to modern architecture - it was its critical motivating factor. This desire among architects to make life better for people got lost in the Sixties and Seventies when their Utopian ideals were realised in dreadful concrete blocks.
Worse, in the Eighties, that era of conspicuous consumption, all pretence of social housing being worthy of good design was abandoned. In his relentless pursuit of housing typologies, Pierre d'Avoigne's aims may be a little old fashioned, but his ideas aren't.
The brief for this year's Ideal Homes Exhibition Concept House competition is looking for 20:20 vision and smart thinking for a totally new model for family life. The judges include Kevin Warwick, Professor of Cybernetics at Reading University, and Geoff Crook from the Sensory Design Research laboratory at Central St Martins. Competition entries and the brief can be obtained through RIBA.