The length of time it is taking for a planning inquiry into a revamp of Anglia Square could put the project at risk, the leader of Norwich City Council has warned.
The inquiry over the controversial plans for the Norwich shopping centre will not take place until next year, with 16 days of hearings due to start on January 28.
It would then be likely to take months before a decision is made on whether the £271m scheme, approved by Norwich City Council's planning committee last December, can go ahead.
The matter was called in by communities secretary James Brokenshire after a request to do so by objectors, including Historic England. They were concerned about impact of the development, with its 20-storey tower, on Norwich's character.
The plans would see the 1960s-built shopping centre and neighbouring Sovereign House demolished.
They would be replaced with new blocks, including 1,234 new homes, a cinema, car parks, a 200-bed hotel and a new home for Surrey Chapel.
The call-in means a planning inspector will hear evidence from all sides at a public inquiry.
The inspector will then make a recommendation on whether the scheme should have been granted permission or not.
Mr Brokenshire can choose to follow that advice, or reject it.
Developer Weston Homes is still reviewing its options, with a spokesman saying it was waiting to see how the inquiry unfolds.
The city council is still working on the statement of case it will submit to the inquiry, which has to be lodged by June 21.
And City Hall's Labour leader Alan Waters admitted the drawn-out process increased the risks to the scheme.
He said: "Delay always creates risk, but we will work and prepare for the timetable set by the Planning Inspectorate."
Organisations such as the Norwich Society, the St Augustine's Community Together Residents' Association and the Cathedral Magdalen and St Augustine's Forum, which objected to the plans, have been working on their own submissions to the inquiry.
When City Hall officers recommended permission be granted, they said, although the development and the tower would cause harm, a "compelling case" had been made, with "economic and social benefits" for the city.
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