The Games need Zaha's icon

The Aquatics Centre has always been an icon of the London Olympics. With its big, waving roof, rising to 35 metres above ground, it was the only design unveiled before London won the bid in 2005. It played its part in convincing the International Olympic Committee that London had big ideas for the Games. But as an icon, Zaha Hadid's design has also become a symbol of 2012's doubts and controversies. Just as the Olympic budget as a whole has multiplied, so has the Aquatics Centre's, from £75 million to £303 million.

Last week the BBC ran a story about aspects of the Centre's construction, such as the timber roof, which it maintained was the wrong kind of wood for a swimming pool, which turned out to be something of a damp squib (it is the ceiling, not the roof, which is timber and there is anyway 18 months before it is to be installed). But what it did do was reveal how the Centre has become a target for criticism, reflecting its symbolic importance and the fact that, like London 2012 as a whole, much of the thinking behind it - in the time before the bid was won - was wishful.

The project is a survivor of that era of both aspiration and unreality, from a time when few truly believed that London would win. The notorious budget for the Games as a whole - without allowance for inflation, contingency or VAT - was from the same period. Unlike that now-discarded budget, however, the Aquatics Centre is still there as a project, and it will be there as a finished building in 2012.

The design is a result of a competition run by the London Development Agency, using a brief created by them, in 2004. The LDA is no longer the client for the project - which is now the ODA - and is keeping a notably low profile in relation to the Olympics. For this reason the brief did not, and could not, respond to all the issues that would eventually go with a fully functioning Olympic Aquatics Centre. It has changed significantly since.

The same is true of the budget, which seems to have followed the common British practice - see also the Scottish Parliament - of starting low. The intention might be to impress on all the necessity of keeping budgets tight but it can have the opposite effect. Once the initial estimate is broken, subsequent budgets lack authority.

The competition jury chose Zaha Hadid, strongly urged on by Lord Rogers of Riverside, then the Mayor's adviser on architecture. Hadid is celebrated for many reasons: she is unquestionably the most famous female architect who has ever lived, and she is possibly the most famous architect living today.

She is also the most prominent example of a recurring type: the Londonbased architect, internationally renowned, who never gets to build in her home city. Twenty years ago, Norman Foster, now immensely prolific, was in this position; now it is Hadid. For a while it was questioned whether her designs could be built at all but her current office of 280 staff, creating buildings all over the world, proves otherwise.

She is not the right architect if all you want is a functionalist box, but if you want a building that symbolises a global event, and is intended to be a landmark for decades afterwards, she is one of a small number who can do that. Her designs are, unquestionably, more difficult-to build than the basic minimum but the Aquatics Centre was never supposed to be about the basic minimum.

To this architectural challenge were added other challenges. The building has to incorporate a large bridge, which will be the main route from Stratford station to the Olympics site, expected to carry two-thirds of the visitors to the Games. It is to be built over buried power lines and archaeological remains, on what the ODA call "the most complex part of the site".

The Aquatics Centre has suffered too, as have other Olympic projects, from the legacy of Wembley Stadium, where the contractors underwent both huge losses and press attacks. As a result, the Centre, like the Olympic Stadium, has ended up with only one contractor bidding to build it, out of those deemed compliant with the ODA's rules.

These rules are supposed to protect the ODA's interests. In practice, they have reduced its freedom of action by severely limiting the choice of contractors. Although there are extensive procedures to ensure good value, it is always harder to negotiate a good price when the contractor knows he is the only one in the running. It was reported that one of the price hikes came in response to lastminute demands from the contractor, Balfour Beatty.

The cumulative effect of these degrees of difficulty is the current budget. Lord Rogers has described it as "exceptional value for money" but it's hard to get the ODA to be so unequivocal. It will only say that it "is in line with the revised budget for the Olympics", while pointing out that it will permanently provide the Olympic-sized swimming pools that London currently lacks.

The Centre's difficulties almost led to the abandonment of the current design. Under the former ODA chairman, Jack Lemley, Hadid was "within inches of being fired", according to one person involved. After Lemley went, she remained suspicious that she would "be royally shafted", and it took a meeting with the new chair and chief executive for them to convince her that they wanted her, and for her to show them she wanted to do the job.

In the process Hadid also took on the Olympics minister, Tessa Jowell, who had unwisely laid the blame for the cost overruns on the architect. Hadid won from the minister an almost unprecedented letter of apology.

These battles have now been fought and, notwithstanding squalls about the choice of timber, the building is now starting construction this month. It is, the ODA proudly says, ahead of schedule. Terminal 5 has taught us never to believe a building will work until after it has opened, but there is now no particular reason to believe that the Aquatics Centre will fail any more or less than with the main stadium or the velodrome.

The £303 million price tag still looks high, even taking into account the bridge, the buried power lines and the other extenuating factors. But we may yet be grateful for the wishful idealism that prevailed before the bid was won.

The mood of 2012 is now one of sombre pragmatism, in which every decision has to be ground through the mechanics of cost control. It is currently being debated, for example, whether the hard surfaces for the Olympics landscape will be anything better than Tarmac.

To have at least one project, the Aquatics Centre, that refuses to be crushed by these constraints might prove to be the saving grace of what might otherwise be the accountants' Olympics. Yes, we all want value for money, and the Aquatics Centre may not have reached its current position by the most rational route, but if cost control was the only object, we should not have embarked at all on something as extravagant as the Olympics.