 The keep today is 46 feet ( 14 m ) high and is modelled on early 13th @-@ century English round towers built in the south of the Welsh Marches . As with other Welsh @-@ constructed towers , the entrance is on the first storey , not at ground level ; it may originally have been protected by a porch . The keep had a portcullis which would have been drawn up past the window on the second storey of the tower . While the castle 's flooring has long since disappeared , its interior staircase to the upper storey may still be climbed . This second storey would have formed the main chamber in the keep and had a large fireplace and a latrine . Originally the keep would have had a parapet and battlements , since destroyed . Historian Richard Avent considers it " the finest surviving example of a Welsh round tower " . 
