The measurements are approximately 80' long to the chancel arch and 18.5' wide from N column to S column in the nave. The S aisle is 22' across and the N aisle is a few feet narrower at 18'.

The nave has 7 bays, with 6 Norman octagonal or circular columns 18' or 19' round on each side and the original clerestory, though the clerestory windows above are later. A lofty Norman arch marks the entrance to the chancel. The present oak roof was added between 1893 and 1912 (Kightly, <i>St Mary's</i> 32).