[2][3][4] The county council decided to find a location where it could consolidate its offices and meeting place.

[5][6] Wren House was purchased with the intention of later building a new headquarters for the county council in the grounds, once the First World War was over and finances allowed.

[9][10] The design involved a symmetrical main frontage with twenty-one bays facing onto a central courtyard; the central section of eleven bays, which projected slightly forward, featured a doorway on the ground floor flanked by Ionic order columns supporting an entablature with a pediment above; there was a tall round-headed window between the first and second floors with an open round-headed pediment above; the end sections of the main frontage contained arched carriageways to permit vehicle access to the rear of the site and there were side wings beyond that.

[12][13][14] The main building was altered in the 1960s to accommodate an emergency control centre in case of a nuclear attack.

[17] The Princess Royal attended a reception for the Council of Occupational Therapists in County Hall on 19 April 2010[18] and a major programme of refurbishment works to convert the building into an open-plan working environment was completed in 2011.