Local architect Thomas Lainson's red-brick and terracotta building, in the Queen Anne style, was opened by the Prince and Princess of Wales in 1881.

The future of the Dyke Road site has been uncertain since the move to the new premises was first considered in 2001; Lainson's buildings and their later additions were threatened with demolition until 2009, when a developer was refused planning permission to replace the hospital with flats.

Brighton & Hove City Council's latest planning briefs state that any redevelopment of the site should incorporate Lainson's original building.

[4] Two years later, it moved to the former Church Hill School, a disused building on Dyke Road; Bishop of Chichester Richard Durnford conducted the reopening ceremony on 14 July 1871.

[5] Lainson won the commission for the new hospital in 1880 by submitting a design for a Queen Anne style building of red brick and terracotta.

[4] In November 1918 the hospital made international news with the appointement of Martha Hunter Hoa Hing, a woman doctor of Chinese heritage from British Guiana, as house surgeon.

[15] Meanwhile, developers expressed interest in the Dyke Road site, hoping to acquire and demolish the hospital and redevelop the prime central location with flats.

[4] The planning officer who made the decision stated that the proposed development was too large in scale for the site, affected nearby open space and appeared "bulky [and] overbearing".

[4][17][18] (The council's Conservation Area Character Statement of 2005 stated that the hospital was "an important part of Brighton life and a well known local landmark".

)[18] In March 2010, the council published a planning statement which required the main building (Lainson's original) to be retained as part of any future redevelopment of the site.

[20] This prompted the council to serve notice[note 1] on Taylor Wimpey to tidy the site, make it secure and improve the appearance of the buildings.

[4] To make way for the new facilities, the Royal Sussex County Hospital's renal unit had to be demolished; it was rebuilt on top of the multi-storey car park.

The 1904 extension, consisting of isolation facilities and outpatients' accommodation, was in the Vernacular/Domestic style with half-timbered gables with jettying, prominent mullions and transoms to the bay windows, and a small tower.

[14][23] The exterior has curved corners and is clad in white precast concrete, intended to evoke the painted stucco[14][23] which is closely associated with Brighton's seafront Regency architecture.