People have been flocking to Powerscourt since the house was officially reopened last month by the President, Mrs Robinson. At weekends, there is an almost constant flow of traffic up and down the tree-lined avenue from Eagle Gate, so much so that even the overflow car parks run out of space, and the cash-tills are ringing away merrily in the shops and restaurants.

Far from being "restored", Powerscourt has been virtually turned into a shopping mall. The west wing, with its newly glazed-in courtyard, is cluttered with shops selling knitwear and knick-knacks, T-shirts and teddybears, pottery and pullovers, and all manner of goods aimed at impulse-buying visitors. There's even a "food hall", appropriately enough, in the former kitchen.

Desmond Guinness, former president of the Irish Georgian Society, was so appalled by this scene of rampant commercialism that he couldn't bring himself to go upstairs. "Simply ghastly!" he exclaimed. Others among the great and the good who attended the official re-opening of Powerscourt were more reticent about expressing the reservations they had about it.

Presumably, they averted their eyes from the pretentious, mockGeorgian and "Tudorbethan" detached houses - 100 in all, with PVC windows - which constitute a free-standing suburban estate at Eagle Gate. They are described on a huge billboard as a "superior development of magnificent residences in the garden of Ireland" and have been selling for over £250,000.

This housing estate, though located in a valley setting, compromises the main entrance to Powerscourt Demesne. It is not quite as bad as the early-1970s housing along the main avenue of Castletown, in Co Kildare, built courtesy of Kevin Boland in an almost atavistic response to the bleatings of the "belted earls". However, the Powerscourt version is nevertheless regrettable.

Even more intrusive is the new cement-rendered golf clubhouse, which is clearly visible behind a row of tall trees not far from Richard Castle's great mansion. A pathetic piece of Palladian pastiche, the clubhouse has an off-centre, pedimented portico, with two bays on one side and five on the other, a trio of round-headed arches at the entrance and bulbous vents protruding through the roof.

In 1990, when the Slazengers first sought planning permission for a variety of developments in the grounds, the main selling point was that all of this would fund the restoration of the house, which had been tragically destroyed by fire 16 years earlier. So much emphasis was placed on this aspect of the scheme that some conservationists were prepared to turn a blind eye to the rest of it.

Few of them would have expected that the "restoration" would turn out to be a minimal affair, laden with yet more commercialisation. An oval-shaped sign at the turnstile which marks the entrance to the house proper is inscribed with the pompous slogan "To Have & To Hold". But the ampersand might just as well be a dollar sign, given what's going on around Powerscourt these days.

The architect, James Toomey, is chiefly known for his expertise in retail design, having been responsible for the Powerscourt Townhouse, the St Stephen's Green and Jervis St shopping centres in the middle of Dublin, and the ill-fated Trocadero Centre in London. The authentic restoration of historic buildings is not his forte and, in any case, it was not the brief given to him by his clients, the Slazengers. But why on earth did the £5million budget not extend to cladding the pair of domes on the garden front in copper? The plastic changelings which have been installed there instead have a verdigris colour, mimicking the effect of oxidation on copper, but their lack of authenticity is so obvious that it can be spotted from 1,000 metres. They are a cheap and tacky insult to the house.

Inside, having paid the £4 entrance fee, visitors are treated to a quite limited audio-visual presentation of Powerscourt's history in what was once the entrance hall. Accommodating it in the usual "black box" setting has meant that most of the windows on the ground-floor of the entrance front must remain permanently shuttered and the main door cannot be used for its original purpose.

This first introduction to the house is quite shocking, since the audio-visual unit is surrounded on all sides by bare-brick walls. A photograph of the entrance hall gives a tantalising impression of what it was like before the terrible fire in 1974. Traces of the original plasterwork, including sad remnants of elaborate scallop-shell decoration, are still visible at one end of the room.

Powerscourt had a late 18thcentury grand staircase, in beautifully carved mahogany and with a wrought-iron balustrade. Though a fair stab has been made at replicating the wrought ironwork, the newly installed hardwood staircase is little short of a travesty, its carved (or moulded?) tread ends a pale imitation of what was there. It is also supported by what is presumably a steel structure, which has been crudely boxed in.

The great saloon, or ballroom, of Powerscourt was the finest country house interior in Ireland. A double-cube rising through two storeys, it is chiefly remembered as the place where Princess Grace of Monaco danced at a glittering ball in the 1960s. Like everything else, it was destroyed by the fire in 1974 and arguably represents the worst single loss to our architectural heritage. Only fire-damaged Ionic pilasters and a classical bust in one of the niches remain as tangible evidence of its grandeur, though there are plenty of photographs on show. Otherwise the volume of the ballroom has been simply reinstated, with 16 plain, painted steel columns rising to the full height of the room and more wrought ironwork in a "replica" balustrade around the gallery.

OF the future, one of the panels in the exhibition says: "It is hoped to restore this magnificent room using a combination of traditional craftsmanship and modern technology. The successful restoration at other large houses such as Uppark in Sussex shows the skills used in the 18th century are still alive today." At Uppark, however, restoration started soon after it was destroyed by fire.

Though the Powerscourt project was developed with the aid of EU funding under Bord Failte's tourism programme, no effort has been made to replicate any of its plasterwork ceilings, such as the one which adorned the dining room, now transformed into a quite pleasant cafe bar. A careful sifting of the rubble - which was not done, apparently - would have helped here. Of course, it is very welcome that Powerscourt lives again and that numerous people can enjoy having coffee and cakes on its terrace, whatever about going shopping. More importantly, it has a new roof, the walls which were threatening to tumble have been stabilised and the whole enterprise provides 50 jobs. But that is where the congratulations must end, at least for the moment.