Pevsner, in the Huntingdonshire volume of his series on the Buildings of England, describes it as one of the largest most uniform late mediaeval churches in the county. It is sometimes known as the cathedral of Huntingdonshire. The interior, much more obviously than the exterior, bears the mark of successive generations of worshippers. The present church is, as a place of worship, very much the work of the Victorians: the pews, the pulpit and the choir stalls. The font, at the west end of the nave, is thought to be one of the oldest parts of the building, possibly having come from the Priory. It seems to be not later than Norman. The Chancel is part of the earlier church, as evidenced by the remains of the thirteenth century window in the north side of the sanctuary.
The Lady chapel was added in the fifteenth century. The present communion table is Elizabethan, probably dating from about 1600.
Another fourteenth century feature is the niche in the north wall.
The spectacular stained glass is Victorian much of it by Messrs. Hardmans of Birmingham and the remainder by Clayton & Bell .