Cornwall Council has approved the sale of Old County Hall to Nigel Carpenter who has revealed his plans for the Grade II-listed building if planning permission is granted.
The Truro Spa Hotel will transform the majority of the ground floor into a spa, patisserie and café while the former debating chamber will become an 80-cover brasserie and around 40 bedrooms will be located across the hotel including a number of suites.
For business people on longer visits or who are thinking of relocating there will be 20 specifically-designed long stay suites.
"I am delighted and honoured to have the opportunity to convert this wonderful, historic building into a flagship hotel for Truro," Carpenter said of the acquisition.
"It will provide a much needed facility for the City which will help fuel the growth of our capital. The conversion of Old County Hall to Truro Spa Hotel will create a public facility, which will allow everyone to enjoy the architectural beauty of such an historic building. It will also ensure the building’s conservation for the future," he added.
The new hotel is expected to open in 2014 after the current occupants of the building move out.
Carpenter, who owns the St Michael's Hotel & Spa in nearby Falmouth, said the project would create around 100 local jobs and would see the style and original features of the hall, originally designed in 1890 by TB Silcock, retained. Conference and meeting facilities and a new landscaped garden area will also feature.
The St Michael's Hotel & Spa building in Falmouth underwent a significant refurb over 10 years costing £4m before it was opened.
The sale of the Truro property was completed after a public tender process launched by the council. Malcolm Bell, head of Visit Cornwall, said the proposed development would be transformational for the city by providing a signature hotel which has been sadly missing' in Truro.
"Truro has often been seen as a 'mini Bath' due to its historic city centre and range of shops and eateries. Unfortunately, we have not had the equivalent of The Royal Bath Hotel to entertain and accommodate high end visitors, key visiting business people, let alone potential investors to Cornwall," he added.