Last month I was the first Western journalist to be given a full tour of Beijing's Olympic Park. Expectations were high. When the world's gaze falls on Beijing on August 8, the Chinese want their Olympic buildings to dazzle. And as long as the world's gaze remains mainly on the Herzog & de Meuron-designed national stadium, they'll succeed. It is amazing. There's nothing like it in the world. As an image, it is exactly what Beijing's Olympic committee wants beamed around the world as the image of new China, as instantly get-able as their cheesy slogan: “One World, One Dream”.

For a nation that deeply values formal architectural symbolism, creating an iconic shape that simultaneously evokes Heaven (a circle) and the auspicious bird's nest was genius on the part of the architects. But so mesmerising has it become that nobody mentions the small matter of the 2,800-acre Olympic park and 31 other venues surrounding it. This is probably a good thing. Because the “bird's nest” might be the ultimate in architectural eye candy, but its neighbours are not. Architecturally at least, the Beijing Olympics are a flop.

Two months before the Games begin, the Olympic park's 4m (12ft) high steel perimeter fence is ringed with stony-faced soldiers, protecting it from sightseers - hundreds, maybe thousands of them, here to get that killer good-luck photo of Them with It. Cars crawl, while snappers scramble up mounds of unlaid paving stones, and stretch mobile phones over the fence for a shot to show the folks back home. For those without cameras, Casio-carrying entrepreneurs offer “instant memories”, alongside touts who open their jackets to reveal, hanging inside, knock-off miniatures of the bird's nest - “in gold, in gold”.

Getting closer than this is well-nigh impossible. Until August this is Beijing's new Forbidden City. So I am lucky indeed to be the other side of the soldiers.

The stadium looks impossible, unreal. From afar it appears neatly woven, but up close, the exterior steel lattice, what Pierre de Meuron calls the “architectural forest” looks impossibly complex. Inside the nest sits the red-painted concrete “egg” holding 91,000 seats - almost circular. But the real drama explodes in the space between this and the exterior nest, where jagged walkways and staircases weave between the frenzied branches, a true architectural forest, and views are thrown deep between the trees or out into Beijing. Unfortunately, this most stupendous of buildings throws the barren monumental park over which it reigns into even more stark relief.

The Chinese, we always hear, can accomplish miracles. Here they truly do achieve the impossible: a place at once awe-inspiring and banal. Imagine a trading estate outside Daventry inflated into Mao-style monumentalism. Few of the venues - most brand new - rise above the mundane. Of the more high-profile, the bird's nests's neighbour, the National Aquatics Centre or “water cube”, is a one-trick pony, though it is quite a trick. The Australian architects PTW, along with Arup engineers, the China State Construction Engineering Corporation and the Shenzhen Design Institute, have tried to out-icon its neighbour with a box of bubbles. The building's material - ETFE, a sort of architectural bubblewrap, reinforced with a steel cage, 99 per cent lighter than glass, and far more efficient at transmitting light and insulating - creates a form designed to cut energy costs by 30 per cent. They like to show this one lit up blue at night like psychedelic bubblebath, perhaps because up close in daylight it looks cheap and - inevitably - plasticky. The interior is about as thrilling as your council swimming baths.

Next door is Digital Beijing, an ominous-sounding “data and control centre” by the Chinese architect Pei Zhu. It is shaped, cheesily, like a mainframe computer from the 1960s, cut with linear glass strips evoking a circuit board. Four gloomy stone slabs, divided by glass atria, do an excellent Orwellian Ministry of Truth impression. It's slightly less spirit-crushing inside.

Finishing the main quartet is the national indoor stadium, by the German architects Gloeckner, of which there is nothing of interest to say except that it has a curvy roof. As one of the centrepieces of the world's biggest event, therefore, it's something of a letdown.

But it's the park itself that really disappoints, relentless in its overbearing scale, dreariness and inhumanity. It was planned by the Boston firm Sasaki Associates, and set with maximum symbolism on the strict north-south axis that gives Beijing its structure, skewering the Forbidden City, Tiananmen Square, Mao's Mausoleum and the hill in Jingshan Park where the last Ming emperor hanged himself.

It is full of fascistic plazas, crummy detailing, feeble set-pieces with nothing but conifers and spindly trees for shade in the August heat, and is so vast that it would take the Yellow River rerouted to keep it green come August. All this is suspended within an Alphaville edge-of-city site with scant relationship with the rest of Beijing.

Plans for the site's legacy are opaque, and this could well become the white elephant to end all white elephants. I wasn't expecting subtle urban planning from the country that throws up ten-lane motorways every other day. But, given the hoopla, I wasn't expecting this. We - myself included - have mocked London's “flatpack Olympics” plans for 2012, while holding up China's “anything-you-can-do-we-can-do-bigger” monumentalism as a model. Time to eat our hats.

Parade of the uglies: other Chinese Olympic venuesLaoshan Velodrome (above)

Are we still on ration books? This venue, by the German velodrome experts Schürmann, leaps straight out of Dan Dare, the spitting image of Ralph Tubb's Dome of Discovery for the Festival of Britain, only what was innovative, striking and futuristic back before Sputnik, looks hackneyed and dated now that the future has arrived without jetpacks and Ming the Merciless.

Basketball Gymnasium

OK, it's not bad. Does the same trick as the “water cube”, only the Beijing Architecture Research Institute's version is slightly better executed. The interior is more refined, and better integrated with the box's show-off façade, an abstract box of gold-coloured steel slats which from afar look like bamboo, but, perforated, seep in light during the day and glow alluringly at night.

Shooting Range Hall

Another dead ringer for a provincial multiplex, by Zhuang Weimin, with one show-off party trick, a massive shell-shaped cantilever. Weimin has described the design as “simple and natural”. We call it boring as hell.

Tennis Centre

This, by China Construction Design International, is meant to resemble a cute, 12-petalled flower unfurling in the sun. Instead it looks like the jaws of a giant alien robot bursting from the earth ready to gobble the universe.

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