Clarence House, 4-10 May Street Upper / Arthur Street, Belfast, BT1 4NJ

Clarence House is a former Church of Ireland office building, constructed in 1865–66 to designs by the architectural firm Lanyon, Lynn and Lanyon, with the Venetian Gothic detailing attributed to W.H. Lynn. It stands on a corner site to the east of Donegall Square, with its principal elevation facing south onto May Street and its rear elevation fronting onto Clarence Place Mews. It is one of the finest examples of Ruskinian Venetian Gothic architecture in Belfast, and its design, proportions, and ornamental richness reflect both Lynn's scholarly approach to the style and the broader commercial and institutional development of the city centre in the Victorian period.

The building is asymmetrical in plan, rectangular overall, and rises two storeys over a basement with an attic storey. It is built of polychromatic brick — red brick to the ground floor with yellow and black brick courses, and yellow brick to the first floor with red brick courses — laid throughout in Flemish bond. Continuous sandstone sill and impost courses run across all elevations, and the base of the building is defined by a projecting uncoursed squared sandstone plinth course. The hipped roof is clad in natural slate and carries two tall polychromatic brick chimneystacks to the front pitch, each with stone coping and string courses. The eaves are deeply corbelled in red brick with brick cogging and a geometric apron, supported on a stone eaves course, with ogee-moulded cast-iron guttering and cast-iron downpipes.

The principal south elevation is six windows wide with two asymmetrically placed door openings. The first-floor window openings are decorative pointed-headed lights formed in flush gauged polychromatic brick with carved sandstone voussoirs rising from a continuous sandstone impost moulding. Each opening contains a recessed Venetian stone arched light comprising a pair of pointed-headed lights with bowtel surrounds and central colonettes with stiff-leaf capitals, a glazed oculus above, and three carved discs. This window type also appears at the easternmost bay at ground-floor level. All first-floor windows rest on a continuous sandstone sill course, below which runs a continuous red and yellow brick panel with a carved stone plaque bearing blind shields beneath each window. The ground floor is surmounted by a further continuous stone string course and brick cogging course.

Above the principal entrance, a recessed stone surround frames two square-headed window openings and a decoratively carved overpanel, opening onto a stone balcony with a Gothic arcaded balustrade resting on four decorative sandstone brackets. To the westernmost bay at ground-floor level, the principal door opening is depressed and pointed-headed, formed in chamfered red and black gauged brick with a flush sandstone keystone and springer stones rising from the continuous impost course. Either side of this entrance are inset polished stone columns with stiff-leaf capitals, set within a sandstone ashlar block-and-start surround rising from the plinth course. The double-leaf timber doors have decoratively chamfered flat panels and open onto a sandstone step and three limestone steps down to the pavement.

To the east end of the south elevation is a further pointed-headed door opening with a voussoired buff and red sandstone head and hood moulding rising from the continuous impost course. This opening is also flanked by inset columns and has a deeply recessed carved sandstone surround comprising a square-headed opening with a stop-chamfered head, curved corners, and bowtel stop-chamfered jambs, with matching double-leaf doors. Above the door is a pointed-headed carved sandstone panel with a bowtel surround and ribbon carving inscribed "Church of Ireland Young Men's Society Established January 1856". The door opens onto a sandstone platform and three stone steps extending to the public pavement.

The ground-floor window openings throughout are depressed and pointed-headed, with heads formed in flush red and black brick with sandstone keystones and springer stones rising from the continuous stone impost course, resting on a continuous sandstone sill course. These now contain replacement single-pane timber sash windows. The first-floor openings now contain replacement timber casement windows. Square-headed basement openings are set within the plinth course and fitted with timber louvres and steel grilles.

The west side elevation is abutted by the adjoining building at No. 9 May Street. The north rear elevation, which fronts onto Clarence Place Mews and provides vehicular access to the basement, is seven windows wide. The western five bays are built in plain red brick, while the easternmost bay continues the polychromatic decorative treatment seen on the other elevations. This easternmost bay has two pointed-headed window openings to the first floor and two square-headed openings to the ground floor, all formed in gauged red brick with replacement timber windows and brick facade detailing matching the front elevation. The five plainer western bays have gauged brick pointed-headed openings to the first floor and gauged brick square-headed openings to the ground floor, all fitted with replacement fixed-pane timber windows. The basement level of the rear elevation is cement rendered with three vehicular openings fitted with steel roller shutters.

Although the interior was largely stripped out around 2007 for modern office use — having previously been completely restructured and refurbished for office use by Lambert Smith Hampton in 1986 — much historic fabric survives, including the elaborate timber roof structure, which field evidence confirms has been retained. The basement is currently used for car parking, and the building is occupied by a property consultancy firm.

The building was constructed for the Church of Ireland Young Men's Society, whose foundation stone was laid on 27th October 1865 and whose hall was completed in November 1866, with the contract executed by builders Fitzpatrick Brothers. The Society had been founded in 1850 for the spiritual, moral and intellectual improvement of its members. The premises originally housed the Society's offices, reading rooms and lecture hall, along with the office, bookstore and rooms of the Diocesan Council of Down, Connor and Dromore, the Church Education Society, offices for Marriage Licences, the Protestant Orphan Society, and caretakers' rooms and storage in the basement. By 1880 the Society's library held an estimated 1,800 volumes. The Society also owned a building opposite on the corner of Upper Arthur Street, which according to early 20th-century records housed a gymnasium and bagatelle rooms. During the late 19th and early 20th centuries, the Belfast-born artist William Gibbes MacKenzie maintained a studio in the building. By 1935 the Young Men's Society no longer occupied the premises, and the building was increasingly given over to commercial letting, including to Alliance Assurance Ltd and Alexander Cowen and Sons Ltd. The building continued to function as offices and as premises for the Diocesan Council and the Protestant Orphan Society until March 1975, after which the Diocesan offices relocated to 17 Talbot Street. By the late 1970s the building had been adapted to house tearooms and a squash centre.

W.H. Lynn's design for this building is noted by both Larmour (1987) and Dixon (1975) as representative of his fully realised and scholarly approach to the Venetian Gothic style, comparable to his designs for the Former Water Office and the Library at Queen's University Belfast.