A good marriage of diverse building types is guaranteed in Malmö's old docklands by a 'confetti city' approach to urban design, writes Frank McDonald, Environment Editor

Santiago Calatrava's Turning Torso tower has become an icon for Malmö, the southern Swedish city just half-an-hour by train from Copenhagen. A stunning piece of structural engineering, it rises to a height of 190 metres (623 feet), twisting 90 degrees on the way up.

The Turning Torso is the centrepiece of Malmö's Västra Hamnen (Western Harbour), which used to be one of Europe's largest shipbuilding yards. But like so many other redundant dockland areas, including Dublin's, it is now being redeveloped as a major extension of the city.

However, unlike Dublin's Docklands, Västra Hamnen is characterised by a remarkable architectural diversity, which derives from what its former chief planner Mats Olsson called a "confetti city" approach - by involving as many different architects as possible to avoid monotony.

The opening of the Øresund bridge and tunnel linking Denmark with Sweden six years ago presented Malmö with a challenge and an opportunity. It ran the risk of being dominated by the much larger Danish capital, but fought back to establish itself as Copenhagen's mildly cheeky cousin.

Since 2000, tower cranes have become commonplace in Västra Hamnen, just across the Øresund. Under its masterplan, the emphasis is on getting a good mix of uses with density, quality and diversity - ranging from the 54-storey Turning Torso to an eclectic array of low-rise terraced houses.

Five-storey apartment buildings, usually with shops or cafés at ground level, line the attractive waterfront promenade, which has become Malmö's favourite place for strolling; on the sunny and warm Sunday afternoon we were there, it was thronged with people of all ages, including young children.

Amazingly, the entire area of Västra Hamnen is barrier-free. It is possible for visitors to walk anywhere, even into the courtyards and small streets to the rear lined with terraced houses. Unlike Dublin's Docklands, there are no gates with swipe-card access. Everywhere is public space.

When the area is fully developed, it will have 18,000 residents and 20,000 people working there. The sustainable development agenda has also been taken on board, with hot water supplied by a district heating scheme and extensive use of "green roofs" and pond areas to reduce stormwater run-off.

As a condition of building leases, developers must meet specific requirements in the masterplan on architectural quality, public space and building performance, including energy use. All new homes must be built in such a way that they use less than 105 kilowatt hours per square metre per year.

There's a marina on the seafront and canals, watercourses and urban parks as well as more intimate courtyards, gardens and lanes. One particularly popular place, at least with daredevil kids, is the new skateboard park - a marvellous undulating landscape of shiny-smooth concrete.

Inevitably, the Turning Torso is one of the main attractions of Västra Hamnen. The second tallest residential building in Europe (pipped at the post by a newer one in Moscow), it was inspired by the image of a discus thrower - that is what Calatrava drew when he first sketched it.

The skyscraper consists of nine five-storey cubes that twist as it rises, partially supported by an external steel "scaffold". The seven upper cubes contain 149 apartments, ranging from 45-190sq m (484-2,045sq ft) in floor area, while the lowest two cubes are used as office space by the developers, HSB.

It was a nightmare to build, mainly because so much time was lost due to high winds and sub-zero winter temperatures. Originally estimated at the equivalent of €81.5 million, it ended up costing €174 million - and the developers couldn't make an economic return on their investment.

All of the apartments had to be rented out, rather than sold, because the prices would have been prohibitive.

On average, the rent works out at €92 per sq m (€8.5 per sq ft) - a steal compared to Dublin's exorbitant rental levels - so it's no wonder that they were all let within two months.

"There was a queue of people who wanted to move into the building," says Jan Andersson, HSB's head concierge. "We have residents of all kinds, from 20 to 84 years old, and hundreds of visitors every day. It's like a little city" - except that it has a reception desk manned 24 hours a day.

"We do everything for the residents - take care of post, book taxis and theatre tickets, arrange for laundry and maintenance. There's also a communal room where they can have parties as well as a gym, Jacuzzi and sauna on the 43rd floor. And everyone has their own wine cellar in the basement."

All of the apartments have kitchen units with granite worktops and appliances from Bosch, Gaggenau, Miele and Philippe Starck, as well as a polished limestone floor in the hall, fully tiled bathrooms, oak floors in all other areas, under-floor heating and full-height doors, also in oak.

On the top floor, there is a conference suite with spectacular views over Västra Hamnen, Malmö and the Øresund. All of the windows are tilted at an angle of 4 degrees, as if to remind those indoors of the twisting form, but there is also a real sense of being in a hermetically-sealed building.

Residents can only open flaps on their windows. However, Andersson assured us that there is no danger of the building turning into a "towering inferno"; it is divided into four fire zones, with up to two-hour protection, and the central core includes an escape stairs alongside the lifts.

It has also been designed to withstand wind speeds of up to 25 metres per second - another consideration that will have to be taken into account by architects here with skyscrapers on their drawing boards, such as the 130-metre U2 "twisting tower" planned for Britain Quay in Docklands.

Another important lesson from the Turning Torso experience is that slender towers with complex structures are at the margins of economic viability.

Certainly, HSB has taken a hit on its most ambitious project, and Jan Andersson couldn't say when the company expected it to "wipe its face".

But even if its emblematic Turning Torso had never been erected, the manner in which Västra Hamnen is being developed is the way to go.

It will take another 10 years to be built out, but any visitor can already see that it is heading in the right direction - a model of good urban design and sustainable development.