Beyond the well is the rear wall of the Great Hall, built by the same Percy, refitted by the first duke, and rebuilt in 1863. The vaults below with their segmental ribbing are original, as is part of the rear and north wall and of the bow, whence the cross curtain ran to the Postern Tower. This is still the state dining-room, 60 feet by 24 feet, and the vaults fulfil their original destination as cellars. At this point is placed a modern cloister supporting a corridor, by which a bye-access is given to the suite of state-rooms. The original entrance to the hall was by six open steps from the court.
Next beyond the hall, pointing to the north-east, is a tower, once the kitchen and scullery, but rebuilt for the second time in 1856, and now the drawing-room, 45 feet by 22 feet. Beyond this, along the north-east front, are the saloon, 42 feet by 22 feet, and an ante-room, 22 feet by 22 feet, built in 1750–86, but newly fitted up. Next to these, and forming the north-west angle of the keep, is Prudhoe Tower, the principal tower in the fortress, upon which the flag is hoisted. This contains the library, 55 feet by 24 feet, and presents two grand bays to the east and west, with a deep re-entering angle between them. This also is modern.
Next, on the west front, follows the chapel, built in 1856, a rectangular tower of bold projection, one principal floor, and a high-pitched roof. The two angles are cut off, so as to form a polygonal apse. This conventional east end points, however, south-west.
Then, facing to the south-west, follow two half-round towers, rebuilt 1750–86, containing state bedrooms, and connected by a short curtain, within which is a dressing-room. Finally, between these and the gatehouse, completing the circuit of the keep, and projecting due south, is the gallery, having on the first floor a breadth of one line of five rooms and a corridor, and below, the middle gateway. The rooms are the private apartments of the duke and duchess, and a passage communicating with the kitchens. The gateway, which has a portcullis, is of the date of 1309–15, and built into the south curtain, from the outside of which it projects as a mural tower. The gallery replaced a curtain about 1760, and was rebuilt 1856. The battlements of the gatehouse were probably added about 1407–55.
The entrance to the state apartments is in the central court, beneath the arched vestibule, at the north-west corner. From this a grand flight of steps ascends to an interior vestibule, and thence by a second flight to the guard chamber, which opens into the state-rooms. These are all on the first floor, the basement being occupied by servants’ rooms.
Although the greater part of the keep has been rebuilt in the last and the present century, it still is composed of the seven towers of the early Percies, shown in the plan of 1567, and much, especially of the basement, is old; and what is new is arranged with a close general regard to the older, and, indeed, in many parts, Norman plan. The exterior ditch of the keep is partly filled up, and the drawbridge of the inner gate has been removed. A portcullis remains.
Of the general and exterior enceinte, the most complete and striking portion is the western gateway, a very fine and unaltered example of a gate and barbican of the Edwardian period, 1312–15, in its simplest form. The barbican, about 55 feet long by 32 feet wide, is entered by a large round-headed arch, between a pair of square flanking buttresses, corbelled out above into two turrets, also square. Over the entrance in a sunk panel is a large Percy lion, with their motto, “Espérance.” The arch leads into a passage, 55 feet long by 10 feet wide, for the first 20 feet vaulted, but afterwards open to the sky. This lies between very lofty side walls, embattled each way. On the left, a small side-door led to the counterscarp of the ditch; also on the left another door opens into a mural stair ascending to the battlements. In front is the portal of the gatehouse. This barbican crossed the ditch now filled up. Besides an outer drawbridge, over a loop of the main ditch, it had an inner bridge between its lateral walls, dropping from the gatehouse. This is mentioned in the survey of 1538, and was removed in 1567. The parapets are without machicolations, and the embrasures have no mouldings. The merlons are not looped, and the figures placed upon them date only from 1750–86. Probably in advance of the ditch of this barbican was a barrier or palisade of timber, and the level space in front, commanded by the walls of both town and castle, is what was usually employed for jousting matches or military duels. The adjacent river was a sufficient security against surprise.
The gatehouse, of which the barbican is the covering, is a rectangle 40 feet deep by 45 feet broad, of slight internal and bold external projection, and presenting to the field two half octagonal towers. The passage is vaulted and has the usual defences of a portcullis and gates. The portals are round-headed. There are lateral lodges, entered one from the passage and one from the court.
Entering the court, the curtain on the left, of considerable height, has Norman foundations, 1150, and an Edwardian superstructure, 1350. Outside, a string-course marks the base of the parapet, and the embrasures have a decorated moulding carried all round. The wall extends to the Abbot’s Tower, but upon it is a small rectangular mural tower, called the Avener’s Tower, 1309–15. The Abbot’s Tower, of the same date, caps the north-west angle. It is rectangular and of three stages, the lowest being vaulted and ribbed with segmental arches, as in the Constable’s Tower, and below the Great Hall. The third stage rises clear of the wall, and is reached by a well-stair, which occupies the north-east angle.
From this a short curtain of mixed date, 1150 and 1350, with a low salient, extends to the Falconer’s Tower, also rectangular, rebuilt, though not exactly on the old site, in 1856, and from which a modern curtain wall runs up to the Prudhoe Tower of the keep. Upon this wall stood the Armourer’s Tower, also rectangular, destroyed in 1856, to improve the view from the library. The removal of this and the Falconer’s Tower are said to have been the only subtractions made from the original military works of the castle.