1996 This two level concrete construction Battery Observation Post was built to control the nearby Half Moon Coast Gun Battery. It has a single upper room accessed by a steel door. This room is lit by a glazed observation slot, overlooking Falmouth Bay, with armoured shutters. A painted panorama showing bearings, etc is above the slot.
A trap door in the floor leads to lower room. The complement of 10 would have included range-finders, instrument specialists, and telephonists. Bunk beds were provided in lower room. In 1939-40 two pairs of Lewis machine guns were erected for anti-aircraft fire just outside the door of the BOP on the grass area to the W.
Apart from the Half Moon Battery guns these were the only other armament in the Castle in 1939-40. They were frequently in use against German aircraft. These Lewis guns had been obtained from ships returning from the Dunkirk evacuation. (Information on Lewis guns from ex BSM Stuart Walls, RA).
Currently under refurbishment by English Heritage.