The £47 million scheme, planned for South Africa, provoked a barrage of criticism when it was first unveiled 18 months ago (AJ 25.11.04).
Wilford and Dyson were asked to design a museum and cultural village ( pictured) as part of a major transformation of a wine-growing estate in Lynedoch Valley.
However, Spier Holdings has rejected the proposals and launched an open international competition for an alternative.
The move has prompted questions about whether Wilford and Dyson's vision was sufficiently 'sustainable' for the famously forward-thinking South African landowner.
Speculation continues to mount following the release of the new competition brief, for which all designs must demonstrate a 'new spatial approach- to create a community that will serve as a model for sustainable living elsewhere on the continent and beyond'.
Yet Tanner Methvin, a director of Spier Holdings and a competition judge, was adamant that the scheme's environmental and sustainable credentials played no part in its demise.
Methvin said: 'Wilford and Dyson's concept has been dropped. The list of reasons [behind the decision] is very long, but it was not related to the sustainable nature of the design.'
The new two-stage contest seeks an architect to masterplan a scheme for around 3,000 people which features 'internationally significant' facilities for visual and performance art.
At least 350 practices from 54 countries have already registered for the competition, including 10 British entrants.
Dyson admitted he was disappointed by the move but argued he and Wilford had done everything asked of them.
He said: 'Our brief... was to produce a fine and memorable building and series of spaces representative of African people - this was admirably achieved.
'However, there have been many changes on the client side which are complex - the consequence of which has been a redrafting of the brief.'
Michael Wilford was unavailable for comment.