The hall is austere; the architectural historian John Newman critiqued its decoration as "dilute" and "unfocused", Crook as "anaemic". It features stencilled ceilings and murals which resemble medieval manuscripts. The murals were designed by Horatio Lonsdale and executed by Campbell, Smith & Company. The furniture is by John Chapple, made in Lord Bute's workshops at Cardiff. The tapered chimney of the room, modelled on 15th-century French equivalents, contains a statue carved by Thomas Nicholls. Although the architectural historian Mark Girouard suggested that the statue depicts the Hebrew King David, most historians believe that it shows Lucius of Britain, according to legend the founder of the diocese of Llandaff in nearby Cardiff.