[1] A doorway on the south side of the tower, and originally another opening on the west face, allowed access to the outside.

The tower is constructed of stone rubble and rendered on the outside, and is decorated with vertical limestone pilaster strips and strapwork.

The blind arcading is purely decorative, since the arches and triangles spring from string courses rather than supporting them.

In fact Warwick Rodwell has suggested that the "hopeless jumble" of the arcading at Earls Barton demonstrates it was mere ornament.

The limestone at Barnack was quarried extensively from Anglo-Saxon times and throughout the Middle Ages to build churches and cathedrals including Peterborough and Ely.

It is evident that Anglo-Saxon churches with long and short work and pilaster strips are distributed throughout England where this type of limestone was available, and in East Anglia where the stone was transported.

Nikolaus Pevsner supposed that the lord of the manor regarded the church as an encroachment and planned to demolish it.

He married the niece of William I, Judith, and she was granted land at Buarton, later named Earls Barton.