Cllr Kim Gottlieb is fighting a last-ditch campaign to persuade the council to delay the plans for 184 homes and around 20 new shops.
He believes the redevelopment is too overbearing and will ruin the city centre and must be stopped.
Tomorrow the council Cabinet, as the landowner, is poised to allow its co-developer Henderson to make a new planning application to revise the scheme that already has planning permission.
In a highly unusual move Cllr Gottlieb, a Conservative, wrote a report for the overview and scrutiny committee calling for an independent investigation into how the scheme has been handled.
The report was only received on Monday morning but committee chairman Chris Pines allowed it onto the agenda.
In a hard-hitting report Cllr Gottlieb said the “council lacked the requisite experience and competence in the management of the project….Members both inside and outside of the Cabinet are not being properly advised, and the fact that the public too is being misled, is a major flaw in the process.”
Other councillors on the overview and scrutiny committee also criticised aspects of the scheme to regenerate a large chunk of the city centre.
Cllr Robert Sanders said it would be “commercial suicide” for the council to allow Henderson to put in the application, as up till that point the council has absolute discretion about any alterations. He said the council was surrendering its negotiating strength.
The existing permission is for 307 homes, of which 35 per cent must be affordable, offices, shops and a new bus station. Henderson and the city council want to reduce the number of homes to 184 and increase retail space by some 55 per cent and drop the bus station.
Cllr Malcolm Wright said he was concerned about car parking as the new plans had fewer public spaces.
Deputy council leader Victoria Weston said the permitted scheme needed to be updated and improved. “I’m reassured that we are advised this represents a good deal for the council and the city. Delay will achieve nothing. It will be a dereliction of our duty. What is so bad about a scheme that has retailers queuing up to take space?”
Kevin Warren, head of estates at the council, said Henderson could walk away and a new scheme now would take four to five years to being to fruition.