Fine Early English-style interior faced in dressed Bath stone. The tower chamber at the W end has a vaulted roof, the 4 moulded ribs joining a circle at the apex. Door to far W of N side with pointed arched head. Tall pointed tower arch with 4 orders of mouldings on 4 attached round shafts with ringed capitals and bases. Nave with 4-bay arcades. Double chamfered pointed arches on compound columns with ringed capitals and bases. The 3rd arches from the W end have the most ornate columns, with clustered shafts of different sizes, some filleted. String course above each arcade from which attached shafts rise above the spandrels of the arches. These have ringed corbels and bases, squared capitals and neck rings which continue as hoodmoulds over the clerestorey windows. The clerestorey openings have roll mouldings which continue down to the string course, but below the windows to each side is a blind triforium with round arches, the blockings pierced by quatrefoils. The nave has a 6-bay tie beam roof with collars supported by arched braces. Cusped struts above collar and windbraces. The E two bays, above the crossing, are shorter. Quarry tile floor.
Aisle windows with splayed reveals and sills. Sill band from which short attached shafts rise, supporting the ribs of the quadripartite vaulted roof. The transverse ribs are chamfered, the narrower diagonal ribs with keeled mouldings. Transept arches similar to tower arch with 3 orders of mouldings. The chancel arch is also of 3 orders but is more ornate, the outer order with keel mouldings and dog-tooth enrichment, while the outer attached shafts are of dark grey Purbeck marble. The chancel has a 3-bay quadripartite vaulted roof, the ribs enriched with dog-tooth and supported on Purbeck marble shafts which rise from the string course above 2-bay arcades. These are highly enriched with dentils and dog-tooth mouldings. The S arcade has compound columns, the attached shafts of alternating stone and marble. Two-arch inner arcadings with quatrefoil above the spandrels decorated with flower bosses. Above the arcades are pairs of clerestorey windows, with a single window further E, the jambs with attached shafts and decorated mouldings, and with quatrefoils above the spandrels. Blind triforium beneath consisting of 2 pointed arches on marble columns with dog-tooth enrichment. Similar N arcade, the R arch blind and the L arch containing the organ. Responds of the 3 stepped lancets at the E end are of 3 clustered shafts supporting moulded rear arches with dog tooth enrichment. The outer jambs have 2 shafts of Purbeck marble.
The S chapel has a 3-bay quadripartite vaulted roof with additional ribs to the apsidal E end. As in the aisles, the ribs are supported on short attached shafts which rise from the sill band. Dog-tooth enrichment and dentils throughout. Encaustic tile floor.
Pale marble font to SW of nave by Robert Davison; round bowl in square surround decorated with blind trefoiled lancets supported on 4 grey marble shafts with ringed capitals and bases. Octagonal pulpit of Portland stone with Purbeck marble columns to each angle. Openwork arch to each face, of 2 lights with a quatrefoil above, and with high relief foliate decoration. Narrower base with stylised blind trefoils. Low stone screen in front of chancel with chamfered coping, between which are highly ornate wrought iron gates with scrollwork and tall finials. Similar iron screen to arcade dividing chancel and chapel. To their E, 3-seat sedilia with moulded pointed arches supported on Purbeck marble columns, under high gablets. Choir stalls with blind trefoiled arches to front.
Stained glass: The E windows of the chapel bear angels by Clayton & Bell, given in 1902 and 1904 by Major Thomas Gray and Emily Talbot, respectively. To its R is a memorial to Lieutenant Rupert Price Hallowes VC who died in the Great War in 1915, by Powell's, and depicting the archangels Michael and Gabriel. Two further windows in chapel to the Cound family, depicting heavenly gifts, by L C Evetts, 1970s. The S aisle has 3 stained glass windows, memorials to the David family, by Clayton & Bell (that to the L undergoing restoration). W windows of aisles, to Olivia and William George (d. 1971 and 1978) by L C Evetts and depicting the Virgin as Queen of Heaven and St Theodore. To N aisle, 3 windows by Powell's, 1950s, including acts of healing. The E window lancets depict Christ between St Theodore and St David, by Timothy Lewis of the Swansea School of Art, 1983.