In its north wall is a small lancet doorway, leading to a well-stair, but probably always closed. A west door leads through a short passage into the lodge, now a police barrack. This lodge resembles closely that on the south side, save that the east recess is closed up, and the fireplace, the brackets of which are original, occupies the north-east face. The upper part of this chamber, towards the ditch, has been pierced, probably for musketry, so as to command the approach from Tower Street. In the north-east angle of this gatehouse is a well-stair, entered by a separate door from the east and outer side. [Illustration: BYWARD TOWER.—FIRST FLOOR.] The first floor contains two large octagonal chambers in the towers. The staircase opens into one of these in the north-east angle, and a chamber 8 feet square occupies the south-east angle. The rear wall between these two turrets is wanting, so that this gatehouse, with its portcullis chamber, was intended to be open in the rear, or was closed, as now, by a lath-and-plaster brattice. There was a small window to the west, over the entrance-gate, looking on the bridge. The arrangements of the second floor are still more simple. The staircase remains, and the two octagon chambers, but the small south-east chamber is wanting. The rear is open. At the battlement level the staircase and its turret cease. There is now nothing above the parapet. [Illustration] In the rear of and attached to the south-east part of this gatehouse is a low tower, of later date, intended to cover a postern bridge, traversing the south ditch, and dropping on the quay. The tower is rectangular in plan, 14 feet broad and 29 feet long, besides an acute salient of 12 feet more, which projects into the south ditch, and prevents it from being raked.