The Southbank Centre has put its planning application for a major redevelopment on hold for three months following a range of opposition.
Mayor of London Boris Johnson intervened recently to say he could not back the 'Festival Wing' development plans if they involved the loss of a space used by skateboarders under the Queen Elizabeth Hall.
Last summer, National Theatre artistic director Nicholas Hytner submitted a 3,600 word objection to the £120 million plans, contesting that the proposed work, designed by British architecture firm Feilden Clegg Bradley, will lead to "segmentation" of the South Bank area.
Rick Haythornthwaite, chairman of Southbank Centre, said the decision to put the application on hold was a "big setback" for the development.
"The case for closing the project down right now is compelling but we feel we owe a last ditch revival attempt to the many people that have supported us over the past four years of planning, not least the Arts Council England," Haythornthwaite said.
"Boris Johnson and Lambeth Council have both made clear that they wish to see the scheme proceed and we look forward to hearing their ideas."
He insisted "our battle has never been with the skateboarders", but "against the economics of bringing a set of crumbling and inefficient buildings into the 21st century, in the context of declining public funding."
Southbank Centre's board will now have to try and find an alternative funding model for the scheme, which will see a large glazed extension added to the Queen Elizabeth Hall, Purcell Room and Hayward Gallery complex.
A spokeswoman added: "It is far from clear how the scheme might now proceed without exposing Southbank Centre to unacceptable levels of financial risk but it has committed to a final three month search with all parties, including the Mayor's Office, Lambeth Council and the skateboarders."