[1] Additional facilities acquired included a local militia barracks (originally designed by Thomas Mainwaring Penson) which was converted for use as council offices in the late 1880s.

[4][a] The new building, which was designed by the county architect, Robert Harvey, in the brutalist style and influenced by the work of Frank Lloyd Wright, was completed in October 1967.

[3] The design for the seven-storey building, which involved a series a parallel wings, featured continuous rows of windows, every second of which had a heavy concrete surround: it was officially opened as the Shire Hall by Princess Margaret, Countess of Snowdon in May 1968.

By 2018, County Hall was proving very costly to maintain, while Unilever's lease of Unity House had ended and the council had tried to sell it without success.

[9][10] The rear wings of County Hall were then demolished in 2020, retaining only the front part of the building which includes the council chamber and some office space.