The crypt is the oldest part of the church. It consists of two rooms.
The inner or western room has a fine vaulted roof with sandstone ribs. The eastern wall of this inner room contains two very good examples of 12th century lancet windows and traces of what may be a blocked-up Norman doorway. In the back wall of this room there are the remains of an aumbry (a small cupboard, usually near an altar where the reserved sacrament is kept for administering to the sick). The doorway leading to the stairs to the vestry used to lead to a staircase connecting with the chancel above.
The larger outer room is part of the 15th century extension and has a barrel-vaulted roof and a small blocked perpendicular-style doorway leading by a spiral staircase to the north side of the chancel, as well as a wooden door to the archway. There is also a cast-iron plaque detailing the increased seating resulting from Goodwin’s restoration; this is almost the same as the plaque in the south porch.