18 Gun Battery And Flanking Battery, Kings Stairs, Sallyport, Pointbarracks

Fortifications, now monument. The Eighteen Gun Battery and Flanking Battery are late 17th-century fortifications designed by Sir Bernard de Gomme. They were reconstructed between 1847 and 1850, when the casements were deepened and a second tier of three gun ports was added to the Flanking Battery.

The Eighteen Gun Battery is built of ashlar stone with mid-19th-century brickwork in Flemish bond to the north face and the Flanking Battery. The roof is stone-paved. The structure comprises 12 bays at one storey, with the Flanking Battery rising to two storeys. Facing Broad Street on the left and at the centre are two-leaf boarded doors, each set beneath a segmental brick arch. Across the front are 12 tunnel-vaulted casements, each with a round-headed stone gun port facing seaward (now blocked) set within a splayed recess with stone voussoir segmental arch. The fifth bay from the north features a late 18th-century sallyport known as "The Common Sallyport", which replaced the original gun port. In front of the fourth bay is a brick and stone stepped stairway leading to roof level, now serving as a promenade pedestrian way. The four casements on the right each have a 20th-century boarded front infill and now function as toilets and stores. A stone band runs across the front with a stone-capped parapet and attached railings.

On the right return is the three-bay, two-storey Flanking Battery set at right angles to the Round Tower, each storey containing three gun ports facing seawards. On the left is a brick and stone stepped stairway to pedestrian level. Between the Flanking Battery and the Round Tower are two casements, each with similar gun ports to the Eighteen Gun Battery.

East of the Eighteen Gun Battery is a short late 16th-century stone sea wall. Further left are the late 17th-century remains of the stone abutment to King James' Gate (demolished around 1870 and re-erected in Burnaby Road), featuring an open tunnel-vaulted recess and a boarded door on the right set beneath a flat stone voussoir arch. Between the former site of King James' Gate and the Square Tower is a late 16th-century stone firing platform with upper parts reconstructed in the 20th century.

On the right is the late 18th-century "Old Sallyport", set beneath a segmental stone arch, which formerly had a stepped landing stage known as "The Kings Stairs". An inscription reads: "From this place naval heroes innumerable have embarked to fight their Country's battles. Near this spot Catherine of Braganza landed in state May 14 1662 previous to her marriage to Charles II at the Domus Dei a week later".

To the north-east of the Round Tower is Point Barracks, built between 1847 and 1850 in Flemish bond brickwork with four tunnel-vaulted chambers. The east-facing front was partly demolished in the 20th century. On the left, 34 stone steps lead to a firing platform. To the left of Point Barracks, adjoining the Round Tower, and on the far right is a one-storey brick gallery with a stone slab roof.