There is a new man-made exclusion zone in east London - a ten-foot-high, jarringly bright, blue plywood fence that twists and turns across Hackney and Stratford. It all but blocks vision at pavement level, and even cuts bridges over the River Lea in half. Since the Olympic Delivery Authority (ODA) completed the 11-mile fence in July 2007, its job has been to keep intruders out of the 500-acre Olympic Park construction zone.
Construction of the main stadium began only in May, so no utopian panorama is yet visible through the few portholes - complete with accompanying text promising exciting developments - cut near the Old Ford Lock. A high vantage point near Pudding Mill Lane DLR station reveals only a field of soil mounds. But otherwise there is no chink in its armour.
The fence, like the Olympic project it guards, has attracted plenty of criticism for dividing an area rich in heritage. The writer Iain Sinclair has described the landscape as "pure Tarkovsky". But it has been left to artists to take action.
On an early June morning the international arts collective the Office for Subversive Architecture (OSA) wheels out its response: an azure blue plywood staircase exactly the same vivid shade - down to the code on the Dulux paint can - as the fence. The stairway, commissioned by the architecture and design magazine Blueprint, is high enough to allow the creative team to spy with steel blue binoculars on the forbidden zone beyond.
Bernd Trümpler and Karsten Huneck, the designers, know the Olympic area well. They were involved as set designers in the surreal short film The Games - directed by Hilary Powell and produced by Optimistic productions. Trümpler jokes that they had debated "cutting a hole in the fence, but we thought that would send the wrong message".
The wall is constantly patrolled by security guards who, according to the Blueprint editor, Vicky Richardson, have been less than pleasant with those getting too close. The platform, she says, is direct action against the ODA's lack of engagement, against its throwing up a barrier around what had been marketed as an all-embracing, utopian and regenerative project for the whole community.
The fence may become a focus for protest against the ODA's failure to engage. "The heavy-handed guards, the fence, security systems. What's the point?" asks Richardson. "It's such a missed opportunity. There's a real enthusiasm for the Olympics, but we'd like more focus on the event than the legacy. There should be a spirit of openness and engagement."
OSA's little staircase forms just part of the riposte to the ODA's failure to consult with the world around the Lea. As compulsory purchase orders swallow up established cultural hubs along with the factories, studios and allotments, protest websites, newsletters and forums have sprung up, too.
While the wall's dioramas of Olympics-inspired "design workshops" by local schools suggest we can't wait for the 2012's legacy, some feel that the here and now is what has been forgotten.