The ancient Sussex fishing village of Brighthelmston, which in the 18th and 19th centuries developed into the fashionable seaside resort of Brighton,[3] lay within the Anglican Diocese of Chichester.

[6] The Diocese established an institute to train female schoolteachers for the Anglican schools in Brighton and the rest of Sussex in Black Lion Street in The Lanes (the ancient heart of the town) in April 1842.

[8] More space was soon needed, so in 1854 it found a site on the west side of Ditchling Road on which to build a larger college.

As World War II approached, the institution closed and the building was auctioned; but before it could be sold, the Royal Engineers requisitioned it for their use during wartime.

A local campaign helped it receive listed status, offering a degree of protection, and the building's future was secured when it was bought and converted into a complex of serviced offices.

[15] Brighton Forum is built on a high, prominent corner position, giving it good visibility from the west and south and long southward views.

[2] Knapped flint is the main building material,[2] augmented by stone dressings and some yellow brickwork to the quoins.

[13] The south walls of the first and seventh bays have prominent five-light oriel windows, canted to form a 1–3–1 pattern of trefoil-headed panes.

[2][13] Above these at first-floor level, and also above the entrance porch, there are three-light trefoil-headed windows set under a segmental arch-shaped hood mould.