Close south of the barn is the Water Tower, a very curious and complete building, early in the Decorated style. It is a mural tower, with no internal projection, having a base 50 feet broad by 30 feet deep, from which it rises as half an octagon, the angles being taken off by two diagonal buttresses, between which, in a projection, is a loop which lights a garderobe. It has a basement and upper floor, and the culvert from the lake discharged under it and washed out its garderobe sewer. In the ground floor is a large fireplace, above which is a handsome chimney-shaft. This seems to have been a kitchen. There is also a mural garderobe. A well-stair, having a spire over its head, leads to the upper storey, the floor of which was of timber, and to the battlements of the tower and of the curtain. The upper floor has a small room appended on the west, with a loop towards the field. The windows are of two lights, trefoil-headed. The roof sloped with a moderate pitch. It was contained within the battlements. Beyond this is a warder’s chamber, chiefly in the wall, but with a slight exterior projection. It contains a large fireplace and a garderobe, and seems of early English or early Decorated date. From hence the curtain was 6 feet thick, and what remains is supported by three Decorated buttresses. Beyond these, a breach of 30 yards extends to Mortimer’s Tower. The walls of this ward, though much repaired and restored, seem to occupy the original Norman lines, and are probably in many places of the date of the keep. The defences outside the wall are formidable. On the north is the ditch cut in the rock, of great depth and breadth, a very necessary defence, for beyond it the ground is at least as high as the base of the keep. This is Clinton End or Clinton Green, upon which are some banks of earth, traces it may be of the great siege by Henry III., who probably encamped on this side. It is curious that no attempt should have been made to fill up the ditch, without which no engine could have been brought to play with effect upon the keep. Probably the strength of the garrison and the frequent sallies they are known to have made prevented this, or faggots may have been used. From Lunn’s Tower to the Water Tower, the ditch is still filled with water, and from thence to Mortimer’s Tower no ditch was needed, the ground being low and wet and at times under water. Then follows the dam, above which the lake covered the south front, as an arm of it did the west front, as far as the Swan Tower. The north was the weak side, the ground there being high; but opposed to this was the keep and the very formidable ditch. It is said that this ditch could be filled from the lake, and the castle thus encircled with water. If so, there must have been a small dam, probably at the bridge in front of the old entrance west of Lunn’s Tower.