It is in the Classical style with two wings, balustraded parapet and a steep pitched roof with tall chimneys and gables.

The main entrance is at the western side of the building and this has a two storey porch and a large oriel window.

In 1947 it was purchased by the newly formed National Health Service for £11,500 and used as an annexe for the Sheffield Children's Hospital.

In 1982 it was sold by the trustees of the former United Sheffield Hospitals for development as a private hospital, however the annexe stood vacant for a number of years but the Sheffield Child Development Study research unit remained in the grounds of the disused annexe.

[3] Thornbury was enlarged and restored in the early 1990s and opened as a private hospital under the management of BMI Healthcare.