Whitewashed plastered walls with plastered large plain arches to crossing. Roofs by Seddon, increasingly elaborate towards chancel. Exposed stone reveals to W windows only. Nave roof of 8 x 12 panels, boarded with bosses and brattished wall plate. Red marble step to crossing. Crossing has chamfered NE angle for tower stair with door at foot. Complex oak roof in 9 panels with heavy beams and pendant bosses, the corner panels have fan vaulting on corbels, the other outer panels slope and the centre has moulded roundel. Very fine mosaic floor to centre aisle and cross aisles by Seddon with inset lozenge panels of fine encaustic tiles of kneeling priest. Transepts have boarded ceilings with heavier ribs, 3x6 panels, each panel subdivided in 4, brattishing and band of quatrefoils to wall-plate. Each transept has 2 pointed recesses in end wall. Chancel has red marble step, with mosaic as in crossing, and encaustic tile panels of three-branch lamp, then another marble step and black marble main chancel flooring in small paving slabs. In sanctuary further three marble steps, with paving of pink marble with black in square or zigzag patterns. Ornate roof with smaller panels along ridge, moulded ribs and carved bosses, and brattished cornice each side above a row of little fan-vaults separating seven half-round panels with shield-bearing angels. This roof conceals a C15 roof. N and S windows are C15 red stone inscribed with rebus and name of William Stratford, Abbot of Vale Royal. Three small square-panelled doors to N: one to base of former roodloft stair, another high on wall to left, and a vestry door further right. Also a pointed S door, all by Seddon, with wrought iron hinges. Fine reredos across E wall in red sandstone and white marble. Red stone outer wall-panelling in squares of rose and vine, in moulded frame. White marble shelf on brackets over pink marble framing behind altar, outer panels white marble with cross on vine background. Frame is stepped over main reredos: 5 white marble inner panels are separated by short half-octagonal red stone columns: alpha and omega each end and 3 long panels, 2 of vine and centre passion flower. Above these three are three white marble lettered panels, 2 with Laus Deo, and centre Gloria in excelsis Deo, also red stone framed. .
Fittings: Font C13 or C14 octagonal ashlar bowl with shallow pairs of pointed recesses each face, on broad octagonal shaft and base, ashlar. Oak and wrought iron C19 cover. Ornate pulpit by Seddon 1879, Beer stone ashlar Gothic, drum with 2 cusped panels with carved stone reliefs of SS John and Paul by H. Stannus, square rosettes and leaf-carving in spandrels flanking, and Gothic column with large capital for book rest. Given by Bishop Basil Jones. Lectern 1906, brass eagle. Pews in nave by Seddon pitch pine with pegged tenon joints, more ornate but similar stalls in crossing with open-arcaded front kneelers and 2 reading desks with triple pointed arches to fronts and scrolled tops to uprights. Nave inner porch in oak with long narrow leaded lights by G.G. Pace, 1960s. Organ in S transept 1885 by Foster & Andrews of Hull, pine case, painted pipes. Timber rails by Seddon, in open grid within panels, the top openings cusped. Timber altar by Seddon with 3 panels each of 4 quatrefoils. Nave and transept light fittings by G.G. Pace. N transept fittings 1936 by Caroe & Passmore including finely carved reredos, panelling each side, altar, rails, lectern, pews and kneelers, all in pale oak. Reredos has carved Crucifixion, St Mary and St John.
S transept exhibition area designed by Peter Lord: pitch pine screen with etched glass panels of winter and spring with words by Dafydd ap Gwilym, by Peter Lord. White glazed tiled floor with red tile border, around two early crosses moved into the church in 1916: short one has crude roll-mould border to roughly hewn cross: uncertainly dated C9-11. Taller cross, the 'Cross of St Padarn' is of granite with Celtic interlace in panels down one face, the other more varied but much eroded has one crude human figure with spiral across the body. Dated to C10. Grey granite monolith seat, kneeler and altar, each with inset gold-enamelled small tile by Andrew Rowe. Wall plaster has incised red line. Small enclosed chambers to each side, to left imitation pointed vault and slate slab floor to chapel of St Padarn with St Padarn window (see below), porcelain panel by Gillian Still of St Padarn and ordeal by boiling water, low slate seat, and niche at S end with etched red chi-rho symbol over massive low slate slab altar with Alpha and Omega incised. To right are two small exhibition rooms entered through screen with 2 further etched glass windows by Lord, summer and spring. The Sulien room has incised slate floor slab and lettered text around wall from Elegy of Rhygyfarch, both by Ieuan Rees. The outer room has historical exhibits in display case by Paul Roberts. Information panels lettered by Mihangel Morgan.
Memorials: Nave: W end slate with relief of priest, to Rev. W.E. Davies (d 1973). S wall: plaque Gladys Greer (d 1934); Matthew Davies Williams of Cwmcynfelin (d 1833), neo-Grec with kneeling child, by E.H. Baily. Chancel floor: slab to the antiquarian Lewis Morris. Chancel N wall from left: E.L. Pryse of Peithyll (d 1888), fine neo-Renaissance with angel opening tomb door; plain plaque to M.J. Fryer (d 1887) by M. W. Johnson; plaque to Jane Loveden (d 1855); broad plaque to Margaret Pryse (d 1798) with 2 weeping cherubs and urn on pedestal; slate plaque framed with fluted pilasters and cornice to Katherine Chichester 1739; large and fine white and grey marble monument to Lewis Pryse of Gogerddan and Woodstock, (d 1779), with rusticated base, pedimented plaque framed by half-balusters, urn and reclining cherubs on pediment, against obelisk. Chancel E, to left: memorial with pilasters and broken pediment to Thomas Pryse of Gogerddan (d 1745); Baroque cartouche with large cherubs, to Cornelius Le Brun of Cologne, son-in-law to John Jones of Nanteos (d 1703); and another below of 1708 with arms and banners, to John Jones (d 1666). Chancel E, to right: Baroque plaque with ornate drapery and scrolls, swan-neck pediment, and arms, to Sir Thomas Powell of Nanteos (d 1705), design by W. Townesend of Oxford, made by R. Wynne of Ruthin. Chancel S: coloured marble memorial to Rev. William Powell of Nanteos (d 1780), Adam-style; Lt W.E.G.P. Powell, killed 1918, with busby and sword; plaque to W.E. Powell of Nanteos (d 1854); plaque with urn to Thomas Powell of Nanteos (d 1797). Very long slate plaque with broken pediment to William Powell (d 1738) and Avarina Le Brun; large memorial to John Pugh Pryse MP (d 1774), with numerous cherubs, one holding portrait relief, attributed to Van der Hagen of Shrewsbury. Plaque to Pryse Loveden MP of Gogerddan (d 1855), by H. Ashton; above is finely carved memorial to Harriet Pryse (d 1813) of mourning cloaked male in Gothic frame, by John Flaxman; plaque to Pryse Pryse MP of Gogerddan (d 1849). Chancel W end: plain plaque to Eliza Rice (d 1846), and plaque with urn to Jane Pryse (d 1846), both by Ashton.
Stained Glass: 3 W windows Abraham, Moses and David, 1894, by Heaton Butler and Bayne. Nave N 1 1887 'Be not afraid', High Victorian style; N 2 1963 by Roy Lewis, modernist; N 3 1985 by John Petts, with symbols on pink and blue. Nave S 1 and 2, Hope and Faith, c1900 by William Morris of Westminster; S 3 Arts and Crafts style by Hugh Arnold 1904, Justice, to Sir G.H.P. Evans of Lovesgrove. S transept: S 3 windows 1930 to Bonsall family; SS Padarn, Teilo and David, conventional, E scenes from Life of St Padarn by Elizabeth Edmundson 1985 in Celtic illuminated manuscript style, W Burma Star window by Celtic Studios 1985, conventional. N transept N 2 windows to Morgans of Nantcaerio c1885 possibly by Heaton, Butler & Bayne; E small 2-light 1878 by J.P. Seddon, inventive dark leading and classical style drawing. W single light c1930 by Heaton, Butler and Bayne to J.T. Morgan of Nantcaerio. Chancel E window 5-light Resurrection with musician angels, very bright, given by G.E. J. Powell of Nanteos, 1884, design by J.P. Seddon with F.J. Shields, made by S. Belham, drawing by H.G. Murray. N window 3-light 1885 given by Hughes of Glynpadarn, presumably by S. Belham; S1 single light Virgin and Child, to EW Jones (d 1879), by Belham, and S 2, 2-light 1884 by S. Belham, Nathan, David and Samuel, given by G.F.W. Powell of Nanteos.