Surreal collage.

An extension to the Dali museum in Figueras is alive to the spirit of the dead artist whose despotic power dominates.

The Teatro-Museo Gala-Salvador Dali in Figueras, which houses a collection of the painter's works, is apparently the second most visited museum in Spain after the Prado.

The town (north of Barcelona near the Spanish border with France) is where Dali was born and died. A large part of its economy is based on a flourishing Dali industry - an irony in itself, because the town's citizens spent considerable energy condemning, and occasionally imprisoning, the youthful Dali for his 'anti-government' outrages. But even at school, the capricious old monster that he became was given to bizarre behaviour exhibiting marked megalomania.

Since his death in 1989, the museum has been able to carry out its plan to extend its premises. Having annexed an adjacent building, it invited the Barcelona practice of Varis Arquitectes to design two new galleries. At present they are to be used for temporary exhibitions, but they will probably eventually accommodate part of the permanent collection. The task of ordering Dali's work has not been easy, for his paranoia during his lifetime impeded any attempts at organisation. Varis Arquitectes' scheme is fundamentally straightforward and sensibly arranged. The annexed building, nineteenth-century and modest in scale, forms a new wing roughly rectangular in shape and attached to the main museum, filling out the irregular corner of a perimeter site, and running back along the street. Two long rectangular galleries have been created, one above the other, linked visually and practically by a double-height foyer and marbled staircase. There are new passages to the main building while services and ancillary accommodation have been installed in the corners left over. Materials are simple and dignified: stained oak floors and painted wooden screens in the galleries, with black granite used in washrooms. Revolving walls on the ground floor permit greater flexibility in designing exhibitions.

But superimposed on such sensible foundations is ironic comment and you wonder about these architects' perception of the artist. Their work in the past (Seltz Bar and Felix Gasull, AR March 1994) has conveyed exuberance - the reverse of Dali's Freudian fantasising and deliquescent obsessions.

There is first of all their external treatment of the new addition. The existing museum, a gaudy confection with Daliesque embellishments, is housed in an old theatre and tower in which the artist lived until his death. The Varis response to the overbearing circumstances was muted: to cover the exterior of the new wing with a coat of ochre paint, leaving only Dali's signature incised into the monochrome crust. In this way, we have a casket of deathly hue signed by the absent master to advertise his presence. You feel the surrealist might appreciate it.

Internally, Dali's presence is pervasive. You climb the stairs to the upper gallery between mirrored walls, where undulating insubstantial handrails flow out to vanishing point, to confront a huge image of the artist's face infinitely reflected and gradually revealed. The image, blown up, has been spread across the entrance to the lift at the head of the stairs, and the effect magnified by reflection is one of despotic menace. Then there are those paintings.