The swimming pool and Turkish baths used by the public since the late 19th century will be closed from this weekend for up to 18 months.

A major refurbishment of the Health Hydro in Milton Road is set to begin, designed to improve many of the spaces available to the public, and in some cases restore them back to something approximating their appearance in their late Victorian heyday.

Some of the work concerns the behind-the-scenes plant such as the heating, but there are plans to improve the changing areas, the main pool, directly link changing rooms to the Turkish baths, create a dance and activity studio and gym and create a better entrance lobby.

Councillor Matty Courtliff, the borough council’s cabinet member for leisure said: “This is such an important, historic project for the town centre and Swindon as a whole.

“This work will not only improve the quality of experience for those visiting the centre but also ensure our heritage is protected.

“Making these improvements now is also estimated to increase the use of the Health Hydro by local residents and visitors. A big increase that will help towards the financial viability of the site.

“We want to make this centre somewhere people will continue to visit for generations to come and the work must be done with the utmost care to ensure its historical value is not lost."

And the council hopes that this phase of work brings more people into the building, as that will be a step towards getting funding for further restorations and improvements such as getting the small pool back into use, and using some of the rooms that were originally constructed for medical consultations and care, as complementary therapy suites.

That funding will be critical because while the works scheduled to start imminently will cost £6.5 million, it was revealed to councillors recently that the full cost of restoring and refurbishing the building could reach as high as £30m.

Project officer Dave Dewart told councillors recently: “There are more phases which would see the Turkish baths improved, community health and meeting spaces created and the small pool restored and opened.

“But that full cost is estimated to be possibly as high as £30m. It’s a historic building but it’s very old and it’s not in the best state of repair and it needs a lot of work.”

Before work starts the council must get approval from its own planning committee for consent to carry out the refurbishments and restorations to the listed building.