Magnificent interiors in severe Roman style. Most of the principal interiors are unaltered retaining original doors, doorcases, marble fireplaces, oak panelling, moulded ceilings, early electrical light fittings etc. Public areas at front of building all faced in Portland stone. At main entrance lobby, steps divide and rise to transverse 3-bay hall; to rear of entrance wall, relief cartouche borne by putti, druid keystone to doorway. Hall has 3 bays; shallow oval domes on pendentives; lunette windows to front and rear (corridor at lunette level to front). Foliage cornice and foliage capitals to wall-piers. Original brass electroliers sprout from foliage (and also to ceilings of lobbies and corridors). To each ends screen of 2 Ionic columns before entrance to Courts 1 & 2 (formerly Crown Court (N) and Nisi Prius Court (S)) each a mirror image. Oak panelled lobbies; both courtrooms square with high lunette windows, flat enriched ceilings, oak panelling, benches, other fittings; gallery with curved frontal over recessed tiered seating. Corridor to each end of hall. Two former magistrates courts (Courts 7 & 8), top-lit, have moulded panelled walls, wooden dado, doorways with segmental pediments; original seating etc. Other courts refurbished. Robing room at SE corner rises 2 storeys into attic, oval oculi, flat enriched ceiling, painted panelling, marble fireplace. Library at SW corner has W section as robing room, separated from E section by Doric columns and pillars; fitted wooden shelves. Rear entrance hall transverse barrel vault with windows to ends; at right angles, rear stair (iron portcullis to arch) divides at landing (wrought iron balustrade) landing with 4 sets of paired Doric columns, and rises again, similar treatment at barrel-vaulted landing. Offices and corridors with simpler classicising treatment to doors and doorcases etc. Former cells with glazed brick facings converted to interview rooms etc.