Bristol City councillors say a £107million revamp of the Bristol Beacon should go ahead despite the “bonkers” cost.
A cross-party group of scrutiny councillors said the project is too important to the city to turn back now and gave it their support.
However, members have called for an inquiry to understand how the cost was allowed to more than double.
The cost of refurbishing the Bristol Beacon, formerly called Colston Hall, was estimated at £48.8million in 2018 and revised to £52.2million a year later.
That figure ballooned to £106.9million after demolition revealed the full extent of the works needed, with an additional £44.5million expected to land on city council taxpayers.
Stephen Peacock, the council’s executive director of growth and regeneration, said “a lot of experts” underestimated the hidden structural problems when the initial costs were estimated.
Mr Peacock shared new pictures from inside the gutted shell of the Grade II listed building to illustrate his point - such as the one below.
He said: “Can I sit here and say that means that nothing else will ever come up? Of course I can’t,” he said.
“But compared with where we were, the building has fully revealed itself.
“There are no hidden nooks and crannies left.”
Green councillor Stephen Clark said he appreciated the issues, but thought the council’s “robust defence” of the huge cost increase struck the wrong tone from a public perspective.