Cogito Erco sum.

Dramatic remodelling of a famous lighting company's premises shows the firm's philosophy and the sophistication of its systems.

In his transformation of Erco's showroom and offices at 38 Dover Street, Pierre Botschi has exercised a painter's awareness of distance and perspective. Standing on the luminous green glass bridge that spans the double-height void at the entrance, your eye is drawn through the showroom, past the milky glass walls of offices beyond, to Verner Panton's dazzling polychromatic image in the far distance. Looking in the opposite direction, from the rear with the translucent glass corridor in the foreground, you see through the delicate tracery of the Victorian shop front to the animation of the street.

Botschi's commission arose out of his earlier scheme to convert a warehouse into headquarters for this British arm of Erco Leuchten, the German parent company. Because of planning difficulties the scheme was never realised but was admired by Kristian Hertzum, his design conscious client. Having decided to reorganise the Dover Street premises, Hertzum asked Botschi to draw up a new scheme. The two did work closely together, and not surprisingly, given the client's provenance (and the fact that he spent his formative years working in Louis Poulsen's office), a Danish presence is detectable in fittings, furniture and most notably colour.

The existing showroom behind the old shopfront always seemed glamorous. Handsomely proportioned with decorative plasterwork, it showed off high technology lighting designed by famous architects and had Andy Warhol's screenprints of Goethe on the walls. (Goethe's dying words are popularly believed to be: 'More light!'.)[1] But it was surrounded by a warren of offices, and basement offices with little natural light were dispiriting. On plan, both levels formed a long thinnish slot stretching back from the street to a narrow courtyard at the rear, overlooked by an undistinguished jumble of neighbouring buildings. The main sources of daylight on the ground floor were the shopfront and gloomy rear terrace.

Botschi's scheme involved a judicious mixture of restoration and wholesale clearance. The fine nineteenth-century facade was stripped of unsightly '60s additions and the character of the original retained. The showroom was simply retouched and painted. More a gallery than a showroom, the space has been frequently used as a gallery for exhibitions of art and architecture and will be so used in the future.

Wherever possible, the interior was cleared of obstructions. Separation of the two levels was always a problem and Botschi has cleverly unified them physically and visually. The new double-height void, its walls finished in pearly polished plaster, absorbs and illuminates the basement. Physically the levels are linked by a flight of finely detailed stairs, their treads of wooden decking and thin balustrading having faintly nautical associations. The stairs lead to offices and meeting rooms created out of old brick vaults, discovered by chance under the pavement during construction. A pale beech floor laid throughout further unifies the different spaces; as does glazing of rear walls at both levels and their external connection by a metal staircase rising from the terrace.

Botschi's lyrical use of glass has transformed the ground floor. The illuminated steel-framed, glass paved bridge over the void makes entry an event; sandblasted glass walls around a normally prosaic boardroom at the rear turn it into a luminous box; the same translucent glass lit from behind conceals a party wall of ugly industrial glazing and screens the managing director's office.

After this luminous oasis the full-scale exposure to riotous colour hits you between the eyes. Erco has always tended towards the monochromatic, so that any colour is a departure (and here one must suspect a Danish influence). As if to emphasise its essentially subterranean nature, Botschi has used his favourite strong blue on some walls, and the elegant little cafe giving onto the terrace has glowing walls of terracotta red.

But it is Verner Panton, Danish architect, designer and experimental colourist, who burns the retina. Stepping onto the terrace you experience the full effect of his extraordinary coloured vision, an enormous bosomy sculpture called Form and Colour that billows over the enclosing wall. Above it is a rainbow-coloured wheel - the spectral image visible from the street.

1 Goethe s final words; Macht coch den zweiten Fensterladen aucn auf damit mehr Lcht Hereinkomme': 'Open the second shutter, so that more light can come in

Architect Botschi Vargas (now Pringle Brandon Botschi): project architect Pierre Botschi

Photographs Richard Glover 

Lighting Erco Lighting

Polished plaster walls Armourcoat

Suspended ceiling Luxalon: Hunter Douglas 

Glazing Solaglas

Ironmongery D-line by Knud Holscher: Algoods

Reception desk Salsa by Pierre Botschi; RAM Engineering

Office furniture USM Haller by Fritz Haller

Tables Nomos by Norman Foster: Tecno; Cafe Lux by Pier Hein: Fritz Hansen/Dovetail; Eames marble table: 20th Century Design; Area (table and bench) by Antonio Citterio: Vitra

Chairs Eames Aluminium Group and Panton by Verner Panton: Vitra; Bertoia: Knoll; Ant by Arne Jacobsen: Fritz Hansen/Dovetail Model 900 trolley and Model 60 stools by Alvar Aalto: Aram Designs.