I learned many things about Britain during a recent 2,000-mile automobile trek through Wales and southern England, but among the most surprising was that Prince Charles, well known for his outspoken opinions about architecture and urban design, is a serious real estate developer.

Ten years ago the Prince of Wales wrote a book, "A Vision of Britain," condemning modern planning and architectural design principles while praising traditional places, structures, ideas and values. Much of his concern focused on threats to the British landscape posed by the pressures of American-style sprawl.

Architects have counter- attacked, suggesting that Prince Charles's attitude is driven by nostalgia. Why, they ask, build structures and communities at the beginning of the 21st century to look like those erected 500 years ago? Isn't such activity better suited to theme parks?

All of this I knew. What I didn't know was that the Prince of Wales--who is also the Duke of Cornwall, which is a territory that has substantial acreage in Britain--is a long-time builder of housing projects, or estates as they are called in the United Kingdom. One of the duchy's latest projects is "Poundbury," a 400-acre community being developed on the western edge of the ancient market town of Dorchester, in Dorset, near England's southern coast. Dorchester is better known to literature lovers as Thomas Hardy's fictional Casterbridge, and the duchy reportedly has owned land there since 1342.

In 1988 the Prince of Wales retained Leon Krier, an internationally known urban design theorist and a traditionalist, to prepare a master plan for Poundbury. Krier was asked "to create an extension of the town that responded to the traditional architecture of Dorset and also incorporated the principles of 'A Vision of Britain.' "

"If development in the countryside is going to take place," Prince Charles has stated, "then it must be done in such a way as to enhance, rather than detract from, the surrounding landscape. This is what we are trying to do at Poundbury."

So I was interested not only in seeing Poundbury's design, but also in understanding how it fitted into its context. Traditionally, English villages, towns and small cities have clear edges where intensely urbanized land abruptly stops to meet intensely green meadows framed by ancient hedgerows and beautiful stone walls. Was Poundbury continuing this tradition?

With construction begun in 1993, only 18.5 acres of Poundbury's first phase have been developed, but Krier's overall plan and the small portion already built suggest that the duchy and its collaborators are fulfilling their aspirations.

Eventually to add 5,000 inhabitants to Dorchester's population and increase its area by a third, Poundbury will not be an enclave or satellite community rising in some farmer's field remote from the town. Rather it is immediately adjacent to built-up neighborhoods, allowing Dorchester to extend its current boundary around the Poundbury property. Existing roads likewise will be extended to ensure the new-old connection. Poundbury is to be a pedestrian-oriented community, within walking distance of employment destinations in Dorchester.

In addition to housing, the Poundbury plan calls for 150 acres of landscaped parks, recreational facilities, schools, shopping and job-generating businesses, some already in operation. The first pub is scheduled to appear soon.

Aesthetically, Poundbury resembles a traditional English village. Although a few major axial boulevards will traverse and interconnect the development as a whole, neighborhood streets are narrow, winding and irregular, recalling the more circumstantial patterns found in medieval settlements.

Streetscapes are defined by a variety of housing types--detached, semi-detached and row houses--that directly abut sidewalks with little or no front yard. Behind each house is a small garden, typically walled in, and a garage for one or two cars. There are public squares, plus landscaped mews and courtyards occupying the interiors of blocks to provide access to garages. No garage faces a street, a stipulation of Poundbury's strict design code, followed by the development's various builders.

According to its marketing brochure, Poundbury's architecture "does not represent any particular period but respects the local vernacular styles" and fundamental principles of "continuity, unity, interdependence, diversity and symbolism." Translation: local stone, stucco or brick; two or three stories with steeply pitched tile or slate roofs; real chimneys; similar eave lines; small-scale, punched-in wall windows with white frames, sash and mullions; and entry doors in street-front facades.

This codified architectural vocabulary undeniably produces coherent picturesqueness and neighborhood intimacy. Poundbury does look like a Dorset village of yesteryear. Of course, in reality its buildings are technologically up-to-date and energy efficient. Double-glazing, high-efficiency boilers, above-normal roof and wall insulation, modern kitchens and baths and smoke detectors are among the features offered.

Housing prices are comparable to those in the United States in desirable urban and suburban locations. Buyers are decidedly professional and middle-class, some retirees from elsewhere in England. Approximately 20 percent of the houses will be "affordable" dwellings for local families to lease or lease/purchase. Built by social housing organizations, affordable units will be interspersed with and indistinguishable from the private housing.

Poundbury can be criticized for its stringent constraints on builders and architects, and for pretending to be an antique. Nevertheless, its ersatz qualities do not seem to be problematic for residents, prospective buyers and most of the public.

Poundbury's implementation was achieved by consensus, not royal edict. The West Dorset District Council, the local planning authority, chose the duchy's land for Dorchester's expansion, in response to increasing housing needs, and approved plans as they evolved. Citizens also were invited to participate in shaping the overall concept.

Now, as the concept becomes reality, it is likely to be a win-win situation all around. Dorchester will have grown geographically and economically in a premeditated, orderly manner. New infrastructure will be synchronized with growth. And a new but still distinct town edge will be established, as befits English tradition.

In Britain, an island nation slightly smaller than Oregon and not blessed with vast supplies of land, the Poundbury development strategy makes perfect sense. It is the most reasonable way to preserve finite pastoral landscapes threatened by growth while still accommodating growth.

Here is a clear alternative to American-style sprawl with its wasteful and destructive use of land, its costly and often inadequate infrastructure, its dispersion of population and its pervasive ugliness. We could learn a lot from Poundbury's example.

Roger K. Lewis is a practicing architect and a professor of architecture at the University of Maryland.