Cromwells Castle

Cromwell's Castle is a gun tower built between 1651 and 1652, with a gun platform added around 1740 by Abraham Tovey, the Master Gunner. The structure is made of randomly coursed granite rubble and features granite platform roofs and stone stacks. The tower has a circular plan, with a rectangular 18th-century gun platform addition on the seaward side that includes an external staircase.

The original entrance is located high up on the south side, where a platform on stone corbels still remains. The tower has rectangular gunports, with the eastern one featuring a raised ovolo-moulded surround. Access to the tower is via granite steps leading to a chamfered arched doorway, which connects to a spiral staircase that leads to the 18th-century platform. This platform has six gun embrasures with segmental arches and an inserted entrance to the tower, flanked by lean-tos that include a guardroom with a fireplace and a latrine.

Inside, the tower has an unlit basement below two accommodation floors, which now have holes for missing floor joists. The upper room features a vaulted roof with ribs, a chamfered surround to the fireplace, and a chamfered segmental-arched relieving arch. The piers dividing the window embrasures have simply moulded bases and capitals. There is a shouldered chamfered segmental-arched entrance to the winder stair that rises through a chamfered arched doorway to the tower platform.

Cromwell's Castle was built in response to a threat from the Dutch, replacing the poorly sited King Charles Castle. It is scheduled as an Ancient Monument.