Modern revival: expansion of one of London's best-loved institutions regenerates a redundant warehouse while retaining the character and integrity of the original. (Interior Design).

Aram Designs in Covent Garden is an institution. More gallery than furniture store, it has been for almost 40 years the place to see and buy the twentieth century's most remarkable works. Its moving spirit, Zeev Aram, was the first in Britain to sell designs by Marcel Breuer, Mies van der Rohe, Achille Castiglioni and Le Corbusier; and can take credit for single-handedly reviving the works of Eileen Gray.

Housed for the last 29 years in a Victorian fruit warehouse on Kean Street, Covent Garden, Aram Designs has now expanded into the adjoining warehouse. The expansion, accompanied by inclusion in the business of two more of the Aram family, Ruth and Daniel, celebrates entry into the twenty-first century and broadens the store's scope. Aram Designs now sells household objects like china, glass and linen as well as furniture and lighting, and in doing so, the family has been at pains not to sacrifice the tradition of simply choosing the best. Such insistence on integrity has been matched by the architects, Walker & Martin, who in stitching the two five-storeyed buildings together, have left intact the industrial character and strength of both structures.

Aram Designs has been in business since 1964. Then a young Israeli designer, Aram had worked for Erno Goldfinger and Basil Spence and had become increasingly frustrated by the dearth of good modern furniture in Britain. The outcome of that frustration was a cool white shop on King's Road -- opened a few months before Terence Conran opened the first branch of Habitat. And in the restless patchouli-scented epicentre of swinging London, flower power and hippiedom that King's Road became, the shop sold Breuer's Bauhaus chairs in tubular steel, Castiglioni's curving Arco lamp designed for Flos, and Le Corbusier's Grand Confort. These works are now considered familiar modern classics, but at that time they were generally perceived as outlandishly spare, even clinical. A few discerned the creative force and grace inherent in the designs and to them, the shop was a small individual oasis of calm rationality, in which strength and elegance were the touchstones.

Aram's move in 1973 into the airy confines of the Covent Garden warehouse, allowed him space to expand his collection-which, allowing changing fashion to ebb and flow around him, he did with an uncompromising eye. By 1973 he had already obtained licences to make works by Le Carbusier and Eileen Gray. To these Aram carefully added contemporary gems, including work by Shiro Kuramata and specially commissioned pieces by architects, artists and designers-Norman Foster, Adrian Gale, Eduardo Paolozzi, Allen Jones, asper Morrison and others - which were made for an exhibition to celebrate 23 years of the company's existence. He has always encouraged young designers and for six years, having exhaustively trawled Britian's degree shows, he held annual exhibitions of work by young graduates. An upper floor of the new store is for experimental works by youthful designers.

Conscious of this background, Walker & Martin have been careful to preserve the original aesthetic, whereby sophisticated pieces of design can be seen against honestly expressed structure. Absorption of the adjoining warehouse means that the store now turns the corner into Drury Lane where a new glazed entrance has been created. The two buildings have been unified by a coat of white paint, and the upper part of the envelope with its Victorian openings preserved. On the ground floor, old windows have been extended down to the pavement and a new one inserted into the flattened corner at the junction of Drury Lane and Kean Street. So the interior of the store is visible all along the street fronts.

Inside, the existing lightwell between the two buildings was glazed over and luminance diffused deep into various levels. A great metal staircase, painted bright red, industrial balustrading with stainless steel mesh, and concrete ramps with cast glass pavement lights, bridge the gap. The aesthetic deliberately drawn from Victorian transport structures suggests connection, movement, circulation. Metal cable trays hovering overhead from a full-height galvanized steel riser reinforce these ideas and permit flexible servicing.

Where necessary, the buildings have been stripped back to the old brick walls and wooden floors, and the big luminous volumes painted white. History has been preserved in archaeological fragments - the original warehouse hoist, an old wooden floor scored by cement tracks simply cleaned and lacquered, differing columns, remnants of moulding and cornice testifying to former habitation.

Against this background, itself a testament to endeavour, the modern objects testify to the great diversity of invention and to human creativity.