Unusually fine, and well-furnished, late medieval interior. Four-bay nave arcades, tall octagonal piers with moulded capitals on square bases, double chamfered arches. Similar but flatter 2-bay chancel arcades. No chancel arch but wide Lady Chapel arch. Earliest roof in north aisle - divided into panels with richly moulded ribs and chamfered rafter infilling, the main ribs jointed into curved braces incorporated into a coved, moulded bressummer piece at wallplate level. Nave and south aisle roofs have very flat-arched profile, plain ribbed panels with moulded tie beams, numerous bosses with armorial and foliage motifs including Tudor Roses. Chancel roof rebuilt 1882 over new corbels and incorporating new arch-braced truss to mark nave division.
Furnishings: Fine late C15 screen of Gloucestershire type extends across nave and aisles, repaired in C19 when paint and gilding removed. Eight bay nave section, shafted muntins extend to the floor, Tudor-arch heads have foliated and cusped tracery, lower sections have 2 panels to each bay with blind tracery and a top frieze of quatrefoil openwork between 2 quatrefoil bands. Double canopy with mortices for loft parapet. West side has tierceron vaulting springing from the muntin capitals. Canopy bressummer frieze with top and drop cresting and 2 bands of stylized vine scroll. The east side of the canopy coved with carved spandrel ornament. There are some irregularities: the Lady Chapel canopy is vaulted both sides and the north aisle has slightly different tracery. C16 parclose screens of Welsh pattern, muntins finish at rail height, panelled dado with blind tracery, narrow lights with cusped tracery under flat head, crested frieze with vine scroll. C15 stalls with traceried fronts and poppy finials across the main and parclose screens, one stall with original book chain. Outstanding early C16 organ case incorporating Gothic and Renaissance details; nationally important as the earliest surviving in the British Isles although not in its original form. Restored and rebuilt 1872 when the present Walker organ installed. The pipes arranged in 5 compartments, 3 of them projecting, the 2 flat sections contain 2 tiers of smaller pipes divided by a richly carved panel with central Tudor Rose, all have elaborate, freely carved, traceried pipe shades. Above is a deep brattishing of pinnacles and semi-circles topped with grotesque beasts. Lower sections have linenfold panelling, some wrongly reset during the restoration.
North aisle Easter sepulchure (or possibly tomb niche) with moulded 4-centred arch. Trefoil-headed piscinas mark the positions of 5 pre-Reformation altars. Monolithic pre-Norman font carved out of local doleritic erratic boulder, massive polished bowl set on 4 thick legs. Tiles by William Godwin of Lugwardine, some medieval tiles reset in north aisle and at entrance to Lady Chapel. Pulpit, reredos and altar-rails by Preedy in Gothic style. East window glass by John Hardman of Birmingham. East end of north aisle has fragment of late C15 glass with St Catherine and her wheel. Also in the north aisle chapel C18 Italian painting of Moses and Aaron and large C17 panelled chest. Some raised and fielded panelling in the north aisle. Three hatchments on the west wall, also C19 tablets to Lewis family. Blocking the Lady Chapel east window a large pyramidal monument with seated woman and portrait medallion to ThomasáLewis (died 1777) and, on south wall of chancel, monument to his wife Ann (died 1785), mourning woman on pyramidal slab flanked by putti. Flat sarcophagus on corbels to John Lewis (d 1797) by Flaxman. In front of the chancel entrance, a floor tablet with foliated cross, possibly C13. Six bells, 1724 by Rudhall of Gloucester.