Internally, octagonal pillars bear parallel arcades of chamfered pointed arches that run along eight bays; these are interrupted only by a lateral arch that divides the western two bays from the rest of the church. The aisles of these bays are partitioned off to form rooms and the arch frames the organ loft. In these two western bays, a plaster vault forms the ceiling while the eastern six bays are covered by a timber barrelled ceiling supported on timber shafts that rise from corbels in the wall above each pillar. A boss rests where each arch between corresponding shafts crosses the longitudinal rib; these depict emblems of Saint Andrew, Saint Margaret, and each person of the Trinity.