Description – Exterior
The new Unitarian chapel was built from ashlar of Millstone Grit Sandstone of high quality, possibly brought in from Derbyshire, where several members of the Potter dynasty had interests in cotton mills. The side elevations are of seven lofty bays divided by buttresses. The latter spring from tall plinths and are treated almost like pilasters, terminating in gablets above a string course which runs above the fenestration and from which rises the coped parapet, level with the tops of the buttresses. The plinth band acts visually as a sill band and the fenestration, in Decorated style, rises from sloping ribbed sills under stopped hood moulds at the top. The roof was of Welsh slate.
These buttresses conjoin at the angles to embrace the turrets of pinnacles at each angle, these being panelled, of square section and topped with conical caps. The E and W ends consist of a steep gable the former containing a fine rose window and a single storey extension, possibly an addition but if so, one completed by 1881 when it appears on a map. The west end contains the well-shafted recessed entrance set beneath a moulded gothic arch containing quatrefoil above a cusped double lancet window above all within a deeply recessed double-recessed arch of three orders rising into the gable. The whole, Clare Hartwell suggests, was inspired by the W end of Peterborough Cathedral, and Rosemary Hill suggests that it is an element of Pugin’s involvement.
Description – Interior
The interior, now largely lost had a pointed plaster ceiling divided into six compartments with bold ribs between. Three moulded arches opened into the westernmost bay, which had a similar vault, a very striking arrangement which must again surely have been a contribution of Pugin rather than of Barry. Three sides of the space contained galleries and the fenestration on the long sides rose from them. Whilst Pugin is associated with ecclesiastical interiors of great richness, the Unitarians would have frowned on such exuberance, and the decorative scheme would have been relatively sober, relying more on architectural effects.
It is not clear whether the choice of Gothic reflected the progressive views of the Manchester Unitarians or the choice of Barry himself. However, Barry was much more at home with various Classical styles, and Gothic may have been the choice of minister William Gaskell and his patrons from Cross Street. It may be that they admired his two local Commissioners’ churches at Stand and Castlefield. If so, the style at Upper Brook Street is less exuberant and enriched, with the detail subsumed into the whole, whereas the two earlier churches were more four-square, with towers (one with a spire) rising from tall projecting porticos made fussy by crenellations, crockets and a superfluity of pinnacles, all repeated very closely at St. Peter, Brighton. This distinct change may well have been the result of Pugin, working up Barry’s instructions, in the same way that he later did at the Palace of Westminster.
Whatever the reason for the choice of Gothic, this chapel; is generally acknowledged to have been amongst the very first dissenting chapels to have been built in that style anywhere in the United Kingdom. It was also the first purpose built Unitarian chapel to be built in the region, although the very first was that built by the Strutt family at Belper in 1782.