Building commenced on St John's Hospital on London Road in 1846, and was completed in 1852, with room for 250 patients. Additions were made in 1855-56, 1860, 1880 and 1916.

The plain Italianate style prevails throughout the large central building, and in all its wings and outbuildings, which occupied about 7 acres. About 8 acres were occupied by gardens, lawns, plantations and roads, and this left about 30 acres for a farm which was worked by the patients.

The average number of patients in 1854 was 244. It was closed in 1990 and is being sympathetically restored and made into beautiful, spacious houses and apartments, the first residents moved in in November 2015.

The hospital was designed by Hamilton and Medland of Gloucester in 1848, and built in 1850-52. The building is of an Italianate design in local 'blue' stone, with dressings of Mansfield stone, and slate, hipped roofs and many stone stacks.

The various additions are in keeping with the style of the original building. The main southern fa├žade of three storeys is dominated by the former superintendent's house. It has a central doorway with a projecting Doric porch with half-columns, entablature and balustrade.

Central to the main projecting gable is an octagonal ashlar cupola topped by a dome and finial. The east and west wings have square pavilions at the corners and round-ended central pavilions. The north entrance front is also three-storeys with a slightly projecting centre and projecting side wings.

The central bay is topped by a pediment with integral clock, behind which is an octagonal cupola with a bell-canted roof. The central cupola and two flanking campanile-like turrets, give the building a distinctive skyline.