City planners have blocked the demolition of a major city centre tower block, saying developers need to submit plans for its replacement.
Developer Sterling Property Ventures and funder Rockspring want to demolish the 1970s NatWest Tower, on the corner of Colmore Row and Newhall Street, and have proposed a small open space while plans for a new building are drawn up.
Those proposals were unveiled earlier this week but the council's planning committee is refusing to allow demolition until the formal planning application for the successor tower is submitted.
They are concerned that, if the plans for the new building fall through, they will be left with an open plot on a prominent city centre conservation area site.
Coun Barry Henley (Lab Brandwood) said: "We shouldn't grant demolition."
He said that, in a couple of months, they should consider both demolition and the new building together.
And he did not want to see the site lumbered with an open space with "plywood building covered in silver foil".
Council officials said they had received assurances the tower application would arrive in due course and that, having gone to the expense of demolishing the tower, the chances of being left without a new building were "very slim".
They said the developers, which acquired the building last year, planned to spend one year on demolition and two years on construction and the open space was just a fall back position.
But Coun Peter Douglas Osborn (Con Weoley) said he wanted a "cast-iron guarantee".