The magnificent Norman tower is one of only 6 round towers in Essex, and with a diameter of 17 feet, is the 3rd largest in the country. The octagonal shingled spire was installed as part of restoration work by Chancellor in 1882. Below the round-headed windows is a Norman doorway with zig-zag ornament and a stonemason's mark carved on the underside of supporting blocks within either side of the arch. The mark here is of a diamond, with central dot, inside two upright lines (see inset). Stonemasonry was a respected trade, and the mark may have served to identify the craftsman and as act as a sign of the quality of the work.