A converted church in Knightsbridge, in central London, just yards from the famous Harrods department store is on the market for $75 million, after being transformed into one of the most opulent homes in London.

The new home comes 15 years after the Diocese of London sold most of St Saviour’s for $1.6 million, because of its shrinking congregations and mounting repair bills.

The church was bought by developers who turned it into a four-storey home with a basement swimming pool, which was owned for six years by the writer of Les Misérables, Alain Boublil.

He sold it for $20 million to a Thai businessman in 2009 who commissioned a second makeover costing an estimated $16  million and lasted almost three years.

The work has upgraded St Saviours again into what the developers describe as “undeniably one of the finest private homes in Knightsbridge”.

Local agents said the 1,100 square metre house is not formally for sale, but is being discreetly “placed” with an elite handful of super-rich foreign buyers.

A brochure reveals the incredible level of luxury at what is now known as St Saviour’s House, originally designed by the architect of Belgrave Square, George Basevi, in 1838.

The basement has been hugely extended and now includes a 10-metre pool and hot tub room with a gold leaf ceiling; a glass encased mini-spa with sauna; a treatment room, a juice bar, and a gym and cinema room with a 120-inch TV screen capable of showing eight programs simultaneously, and which has a ceiling finished with platinum leaf.

A glass and bronze lift-shaft surrounded by a spectacular spiral staircase has been installed through the middle of the home, linking all the floors.

What was once the nave has become a vast drawing room with a 15-metre vaulted ceiling.

There are four main bedrooms and three guest bedroom suites.

Despite the millions lavished on the conversion, many of the original features such as arched windows, oak beams and stone columns, have been preserved.

Churchgoers at St Saviours said the vast conversion had caused “endless aggravation”. One told a local newspaper: “I just pray the next person doesn’t want to gut it again, it all seems madness to us.”

Agents said one problem for St Saviour’s House could be its status as a former Christian place of worship, which could limit its appeal to Jewish and Muslim buyers.