The great gatehouse is 80 feet broad and 54 feet deep, besides which it has two half-round projections in the front and two three-quarter projecting stair-turrets 24 feet diameter at the outer angles of the rear, the former flanking the entrance, the latter communicating with each floor and the ramparts. The entrance passage, 54 feet long by 8 feet broad, is much mutilated, but seems to have had an exterior drawbridge, two grates, folding doors, and a grate at the inner front. The entrance portal has within it a “machecoule,” or _meurtrière_,—that is, an opening from the chamber above—and behind this a portcullis. Then follows a passage 11 feet long, crossed by two ribs, a second portcullis, and a portal arch, upon which rests the west wall of the chapel. Then follows another passage, 20 feet long, entered by gates opening towards the inner ward, and crossed by five broad ribs, with four open spaces. At the end of this is a third portcullis, the groove for which is now closed above at a level too low to allow the grate to be lifted to the height of a cart, while in the arch above is a square cavity or “machecoule.” It would seem that while the wall was rising it was decided not to use these grooves, and that the hole was intended to take the place of the grate as a defence. Beyond this is the inner portal, which, like the outer, has no rebate for a door. In the front division of this long entrance, between the two outer grates, are two loops from the side lodges, which are entered by two doors placed near to the inner end. This passage was covered over with boards, the flooring of the rooms above, and which rested upon the stone ribs. Here, as is often the case, the portcullis groove stops from 1 foot to 18 inches above the door sill, showing that the spikes at the lower end of the grate were of this length. This long entrance passage is further lengthened by the addition of two unequal piers to its internal face. They are blocks of masonry 10 feet thick. That on the south or left had a door whence a narrow staircase of two flights ascended to the front floor. The pier on the right is of less breadth, and was only an abutment to support the arch which connected the two and contained and continued the entrance passage, and on which was the landing at the stair-head.