The keep is an impressive structure. Its stone walls are thick at the base and above. Access was gained by crossing a drawbridge into a central entrance chamber on the first floor. Originally there would have been at least one additional storey. These floors had small rooms built into the thick walls. A timber gallery was built on top of the keep for the visit of Edward, Prince of Wales in 1301. On the ground floor is a vaulted passage that runs all the way around the inside of the keep.