St Mary’s Church occupies the older centre of Clyst St Mary, close to the Roman-aligned road and within reach of the medieval bridge that fixed the village’s position in the landscape. The building is the product of several phases rather than a single medieval campaign. The earliest fabric is probably 13th century, with later 15th‑century work, but the structure visible today is largely the result of 19th‑century enlargement and re‑orientation.
The plan is cruciform. Transepts were added in 1818, extended again in 1840, and lengthened in 1870. A major internal re‑orientation in 1895–96 turned the south transept into the chancel, with the former nave and chancel now functioning as transepts. The whole building is finished in blocked stucco under a slate roof, a typical treatment of the period.
The west tower is late medieval. It has a battlemented parapet, a pronounced string course, and single‑stage construction with two‑light square‑headed belfry openings on all sides. The tower is now encased within the widened footprint of the former nave, probably altered around 1840, producing the symmetrical west front seen today. The west door has a hood mould with floriated terminals, and above it is a window containing three quatrefoils in roundels. A clock in a stone surround is set on the north face.
All the windows are 19th century but belong to two distinct building phases. The three‑light Decorated windows on the north, south and east elevations, with hood moulds and head terminals, appear earlier than the plainer two‑ or three‑light windows without hood moulds on the north wall of the former chancel and the east and west walls of the present chancel. A lean‑to vestry stands to the north‑east, entered through a gabled porch flanked by lancets; the doorway is chamfered with a trefoil head.
Inside, the present nave and chancel have ceiled wagon roofs, while the old chancel retains a boarded wagon roof. A chamfered stone arch marks the former chancel, and a wooden arch of 1895–96 defines the present one. The ritual east window has internal nook shafts with keeled, stiff‑leaf capitals. The five‑bay wooden screen, Perpendicular in style and made locally around 1895–96, belongs to the same phase of work.
The church contains three notable stained‑glass windows by Lavers, Barraud and Westlake, installed in the 1870s. These include the ritual east window and the two flanking windows in the nave. Their quality is high and they form a coherent decorative scheme typical of the firm’s work in Devon during this period.
The churchyard holds monuments to several families associated with the parish. Among them are the Porchers of Winslade House and Edward Cotsford, whose memorial records his service in the East Indies and later public offices. The usual range of 18th‑ and 19th‑century stones survives, reflecting the long continuity of the site.
Although the church was not directly involved in the Second World War, its proximity to Winslade House — used by U.S. Navy Construction Battalions as part of the Countess Wear supply depot system — brought American personnel into the parish. The church itself remained in use throughout, but the wartime presence forms another layer in the building’s wider historical context.
St Mary’s is therefore a composite structure: medieval tower, early‑19th‑century transepts, Victorian re‑orientation, and later fittings. Its fabric records the changing needs and resources of the parish over seven centuries, without attempting to disguise the fact that it has been repeatedly adapted rather than preserved in any single “authentic” medieval form.
