St John the Baptist's church has an early 11thc. W tower with an octagonal upper storey and broach spire of c. 1200, an 11thc. nave to which aisles were added, the N in the late 12thc. and the S, along with its porch, in the 13thc. The chancel has a 12thc. N chapel and a broad S chapel (the Walcot Chapel) of c. 1500. The chancel was lengthened and a wider chancel arch built c. 1300. Shortly afterwards the E part of the S nave aisle was widened to form a chapel, and the N chancel chapel was also rebuilt at this time, with a vestry added to the E of it. There was a major restoration in 1853-55, which included the removal of a 13thc. wall blocking the tower arch and the strengthening of the tower walls with iron bands. In the 1935-37 restoration these bands were removed and a number of openings unblocked.
Construction is of Barnack ashlar, all neatly cut except for the Anglo-Saxon portions, built of large irregular blocks with long and short quoins on the angles. Photographs of the celebrated Anglo-Saxon W tower, tower doorway and chancel arch are included here, but descriptions are confined to the Romanesque work. This comprises the N arcade and N chancel chapel arch, the N doorway and a corbel and capital reset in the S rood-loft stair. Notice has also been taken of the Christ in Majesty relief, now set in the N aisle, which has been variously dated between the early 11th and the 13thc.