Robert Reid, 1810-12; additions and alterations by William Burn, 1825. Severe neo-classical symmetrical 2-storey 11-bay building, with attic storey to advanced centrepiece and end bays; single storey stable range to rear; Burn?s additions include perron stair, single storey pavilions and single storey links to stables. Cream sandstone ashlar; base course, cill course to 1st floor, band course above, dentilled cornice; balustraded parapet between panelled and coped attic storeys; punched windows.
S (COMMERCIAL STREET) ELEVATION: 3-bay pedimented centrepiece with pair of fluted Greek Doric columns set in antis between broad piers, each pier with niche at ground and framed square panel above; Royal arms (carved from wood) in tympanum; 2-leaf panelled door with moulded architrave and cornice; perron steps, panelled to front, with bulbous balusters and piers. 3 bays and broader advanced end bay to either side. Flanking advanced single storey pavilions with window in recessed arch; moulded impost course; cornice and blocking course with raised panelled central tablet. Arrowhead cast-iron railings on flat ashlar bed between pavilions and centrepiece.
W (DOCK PLACE) ELEVATION: at ground, single storey pavilion to S with large rectangular window in recessed segmental-arched panel, moulded impost course, panelled door with 3-pane rectangular fanlight to right, blocking course with raised panelled tablet; coursed single storey rubble screen wall enclosing stable court to S with 2 small windows and door between extends to tall ashlar carriage gateway detailed as pavilion but with 2-leaf boarded gates in round-headed arch. Recessed to N, piend-roofed 2-storey 3-bay end of coursed rubble stables, central window of 1st floor blind. 1st floor of main block with pair of central windows and slightly advanced outer bays.
E (WATERFRONT) ELEVATION: as above, but: S pavilion with round-headed arch and standard window (no door); ashlar screen with 5 bays, panelled door to left with consoled cornice, narrow door to inner left with flanking sidelights, 3 windows to right. Stable pavilion with door to centre at ground.
N (REAR) ELEVATION: 2-storey and attic 8-bay; coursed rubble with ashlar dressings; band course, cornice and parapet to advanced single end bays only; windows to each bay of principal floors. Centre 4 bays advanced with attic windows and pediment. Flanking bays with round- headed loading bay breaking eaves at centre; projecting porch to 3rd bay from left; inner right bays with projecting garage door addition at ground. End pavilions (see above).
STABLE RANGE: coursed rubble 2-storey 12-bay range with stugged ashlar dressings; 4 central bays with irregular fenestration between pair of slightly advanced fronts with recessed archways (blank to left, windows to both floors to right) and blocking courses, 2 bays beyond and taller end bays.
12-pane timber sash and case windows. Grey slates, piended roofs; cast-iron downpipes; decorative rainwater heads stamped GIIIR.
INTERIOR: classical theme continues, much-altered by Burn. Lobby leads via tripartite doorway with elliptical fanlight to oblong central stair-hall with Imperial stair going down to ground level and up to gallery and principal floor; acanthus balusters embossed with lions rampant; oval dome on pendentives and elliptical arches with coffered soffits, opening through smaller elliptical-headed doorways to room each side. To E top-lit Boardroom, with apsidal ended meeting room beyond; to W top-lit arcaded Long Room with D-shaped room beyond. To E at ground Burn's public reception room created in single storey link with direct access; elaborate 9-compartment ceiling on bracketed cornice (now fitted out as exhibition room).