Seán Dunne's soaring scheme for Ballsbridge will need to be scaled down substantially to win approval, writes Frank McDonald, Environment Editor

Famously, when Seán Dunne had nine architectural firms competing for the prize of developing his vision of Ballsbridge, he flew them all over the Jurys and Berkeley Court hotel sites by helicopter. They needed to get a bird's eye view of the terrain which had cost him €379 million, and some of them had never been in Dublin previously.

Ulrik Raysse, design director of Danish architects Henning Larsen, was one of these first-timers. "I didn't know much about Ireland then, except that it had blossomed a lot while Denmark was growing more gradually," he says. "But I think Dublin is quite like Copenhagen. Both are historical cities with centres that haven't been destroyed."

This gave him a "strong understanding of scale", pointing to the need to be "bold and at the same time humble" in designing for Ballsbridge. But what has been proposed is far from humble - a 37- storey tower, 12 metres higher than the Spire in O'Connell Street, and seven other buildings ranging in height from 10 to 18 storeys.

It was while walking around Dublin on his first visit that Raysse spotted the Peppercanister church in Mount Street Crescent and realised that it was one of the city's few perfectly aligned landmarks. And so, his "diamond-cut" tower is placed on the axis of Pembroke Road, "marking a gateway between 19th and 21st century Dublin".

According to him, it's all about "seeing the city with different eyes than people who live in it and taking an overview, a more holistic approach". This includes realising the "great potential" of opening up the two hotel sites with new pedestrian routes going right through it to link Pembroke Road, Lansdowne Road and Shelbourne Road.

Having drawn these lines, the architects then knew where to place the buildings. The glass-and-steel tower, with its highly irregular geometry, would be the big totem, but the other buildings would all be clad in brick "because Dublin is a city of brick" - and also in deference to the grand Victorian houses in the immediate vicinity.

It is clear, however, that everything around the site would be dwarfed by what's planned. Even Lansdowne House, a late-1960s precast concrete office block on the corner of Northumberland Road, would be lower than the 11-storey apartment buildings that would form a staggered line along the southern side of Lansdowne Road.

These blocks would not be cliff-like, however. Their volumes are broken down to seven storeys on the front, with four more stepped back above what Raysse calls "table lands" - much larger than the usual rooftop terraces. "With these setbacks, deep cuts and landscaped gardens, the façade will be all the time changing," he says.

Raysse gets really excited about the 132m tower. "We built a lot of models with different geometrical cuts before deciding on this one. Then we did design studies of the façades [ with Arup, the structural engineers] before coming up with a triple skin that will create a new benchmark for environmental sustainability."

Paul Dunne, an Arup environmental engineer, claims this as a first for Ireland. The tower ("One Berkeley Court") would not be hermetically sealed; instead, it would be able to breathe through windows that could be opened and the stack effect of an atrium, while the residents of its 182 luxury flats would also be shielded from high winds.

Designed to capture maximum daylight, the apartments would all have internal timber louvres to "close down" for bedtime. "So it would have very different perspectives, day and night", Raysse enthuses.

On the lower two floors would be Michael Colgan's cultural centre, with a "burlesque" flavour to give yet another perspective.

"We wanted people to have a new experience, architecturally and spatially," says the youthful-looking design director. The railings would go (and the evergreen oaks, too) to make the two hotel sites much more permeable. Even the corners of buildings at its seven new entrances would all be chamfered, as if to invite outsiders in.

Glazed prisms, up to four metres high, are planned to punctuate the pedestrian streets, offering views through tropical vegetation into an underground shopping mall. The curved street running parallel with Lansdowne Road would also be lined with "high-end" shops, presumably to confirm Ballsbridge as the "new Knightsbridge".

But there aren't any 37-storey towers in Knightsbridge. It is also highly improbable that Henning Larsen Architects would be allowed to build anything like this in Copenhagen. Their Nordea office complex is almost domestic in scale, while the canopied opera house in its harbour is a more bulbous version of Jean Nouvel's in Lucerne.

Larsen's proposal for Ballsbridge is "more dynamic than Danish", Raysee insists. "Cities shouldn't be museums. Ireland, and especially Dublin, is very strong on literature, poetry, music and theatre. But where is the excellence in architecture? What we're trying to do is to raise the bar here, by daring to create a place that's unique."

However, the huge quantum of development being proposed - 536 apartments, a 232-bedroom hotel, two office blocks (one of them billed as an embassy and media complex) and 27,375sq m (294,661sq ft) of retail space, including bars and restaurants - has little to do with architecture; it is driven by the high price paid for two prime sites.

It is also bogus to suggest that this high density scheme will help to solve the problem of sprawl in Dublin. None but the very affluent would be able to buy into it, as no social or affordable housing will be provided on the site. And Mountbrook Homes is hardly sprawl-proof, having built in Celbridge, and Charlesland, beyond Greystones.

The reason why Copenhagen is double the density of Dublin, even though it has roughly the same population, is not because it's peppered with high-rise buildings (it isn't). It has to do with the fact that most people in the Danish capital live in five-storey apartment buildings, rather than two-storey houses with gardens front and rear.

Seán Dunne deserves credit for seeking out the best architectural advice before embarking on his vaultingly ambitious project for Ballsbridge. What Larsen has produced - and there have been up to 25 architects working on it for 18 months - is a high-quality scheme, which includes an impressive three acres of public open space.

But the real issue is whether it's the right horse for this particular course. If it is to have any chance of winning approval from Dublin City Council's planners - and ultimately, An Bord Pleanála - it will have to be substantially scaled down, with the tower and other buildings reduced in height proportionately.

Otherwise, it's not a runner.