In years to come, historians will use the architecture of the 2008 and 2012 Olympics as a cunning indicator of the decline of the west and the rise of the east. In Beijing next year, an army of tens of thousands of labourers, a command economy and untold wealth is creating a landscape of monumental, Phaoronic icons. In London, an army of consultants, an economy of wimpy old public-private finances, and our usual bodged pennypinching when it comes to big projects, is in danger of creating the flat-pack Olympics.

The newly unveiled designs for the main stadium sink the spirit. It’s our own fault. The bar was raised high when those early iconic images of the Lea Valley were used to win us the bid. We were told again and again that these were aspirations, that the realized designs may or may not resemble them. They sure don’t. The "look" of the bid images, with its radical curves and stadium clad seemingly in bubble-wrap, was undoubtedly the work of the bid's co-architects, Foreign Office Architects, rising stars in the architecture world who subsequently distanced themselves from 2012. Their aesthetic vision was useful as marketing brochure iconography, but you didn’t actually think we were going to build it did you?

Since then the Olympics, architecturally, have been a rollercoaster ride. One week we get Tessa reassuring us that it’s OK, architecture is the heart of what we’re doing, etc, etc. Next week she’s addressing the accountants and shaving more off the venues’ budgets. The thrilling, agenda-setting architecture we were promised by implication during the bid, and subsequently by the appointment of excellent architects for the venues, such as Zaha Hadid and Michael Hopkins, is being whittled down to something wafer-thin, tragically underwhelming.

At £496m, though, the new stadium is nearly twice the cost of Beijing’s ($500m approx). So, how come Beijing’s getting so much more bang for its buck? It’s simple: the strength of the pound, the cost of labour and materials in the UK, plus the fact that the 2012 Olympics went to just one consortium to build its main stadium, rather than opening it up to genuine competition, leaving it in no position to negotiate the cost.

The result is the worst of all worlds, deflated architecture at a high price. The architect, Rod Sheard, of HOK Sport speaks of the building’s appropriateness. Part of the brief’s problem was that there is no actual need for this stadium once the Olympics have gone. So, he has created a stadium that can quite literally deflate — 55,000 of its seats will be removed after the Olympic fortnight — and clad in a printed fabric curtain. It’s basically a marquee. In this, he has done the job asked of him, albeit at a cost. I can quite understand the argument about not building monuments and white elephants where none are needed. But the main stadium is meant to be the showstopping jewel in the Olympics’ crown, not something from Ikea fit for a garden party. Where’s the pizzazz? Where’s the showbiz? Where’s the architecture, Tessa?

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