A Croydon Council refurbishment that ran £12 million over budget has failed to replace 1960s windows.
The iconic Fairfield Halls venue was closed for three years, reopening in September 2019.
The revamp cost at least £42 million, way over the original £30 million budget.
The council says the windows were not replaced due to “budget constraints”.
In a question to the council, Councillor Robert Ward said a 2015 cabinet report stated the refurbishment would include replacing windows.
The opposition councillor asked which windows at Fairfield Halls have been replaced with double glazing and which have not.
In a written response, Cllr Oliver Lewis, the cabinet member for regeneration, said that the newly built parts of the development have new windows.
But added that in the existing 1960s building the windows have not been replaced.
He said: “The existing windows have a glazing bed depth that is too narrow to incorporate double glazed units and due to both the buildings local listing and budget constraints they could not be replaced.”
He went on to say that cracked windows were replaced and the frames were refurbished.
The cost of the refurbishment was supposed to be covered by the building of more than 400 flats on neighbouring College Green.
The council had loaned developer Brick by Brick £69 million for the project, which included the revamp, a car park and work on land outside the halls.
But in May it decided to cancel the loan, so the developer will not have to pay it back – Croydon taxpayers could ultimately end up footing the bill.
The council is looking for a buyer for the College Green site to recoup the loan cash.
An independent report into how the project was managed and how much money was spent is being carried out by external auditors Grant Thornton.
The report is yet to be published with no date set for when it will be ready.