The cost of Buxton's Crescent development has spiralled due to “unforeseen” and “unplanned” conservation and restoration costs.
The current “gross value” of the ambitious scheme, which began in 2016 after decades of planning, is now £68.4 million. Of this, Derbyshire County Council is already responsible for £33.5 million.
The new sum is far higher than figures released last year which priced the scheme at £46 million, already more than double the initial budget.
Work was supposed to start in 2003 with an initial completion in 2007 under the guidance of developer Trevor Osborne, who purchased the property in 1993.
However, full-time work only started on the former Georgian spa hotel in May 2016 and the site has been cordoned off since then with ongoing construction and repairs.
The Grade-I listed building is now due to be complete in 2019, some 12 years behind schedule.
However, a report from Derbyshire County Council ahead of cabinet on Thursday, October 11, shows that costs are spiralling.
It states: “During the progression of these works, additional, unforeseen issues with the building have been uncovered which require additional specialist attention in order for the project to be completed.
“As work progresses, it is anticipated that further unplanned conservation and restoration costs will be incurred and there will need to be further discussions with project partners to explore additional funding options.”
The authority has previously approved loans believed to total around £11.39 million for the project.
The Crescent was built in the 1780s by the fifth Duke of Devonshire, it has been vacant since 1992. The iconic building is thought to be essential to boosting tourism in Derbyshire and could create a boost to the local economy of £4.5 million a year.
Councillor Barry Lewis, leader of Derbyshire County Council, said: “Driving economic growth and creating more job opportunities is one of our top priorities and the redevelopment of Buxton Crescent has a key role to play.
“We’re looking closely at Derbyshire’s tourism economy and how we can help build on the fantastic array of attractions already on offer across the county to improve its prosperity.
“Buxton Crescent is a real jewel in Derbyshire’s crown and we look forward to the day when the public can once again enjoy this fabulous Georgian gem.”
In addition to this, the project is to create 140 permanent jobs and 350 construction roles during the repairs and upgrade.
The building would open its doors again as a hotel and spa, with 80 bedrooms and an indoor and an outdoor pool, and space for six shops on the ground floor.
The Crescent and Thermal Spa Experience and development of the Pump Room will also provide a new indoor attraction for residents, visitors, groups and schools.
Once open, it will be run by Hungarian operator Danubius Hotels Group.