[3] This complex group of fortifications is located at the end of Princes Lines and was named after Lt. George Forbes RN, ADC to Prince George of Hesse-Darmstadt, third Earl of Granard (1685-1765) who took part as a midshipman in the attack of 1704 and who fought on shore in the siege of 1727.

In 1761 the British constructed Upper and Lower Forbes' Batteries.

[4] Upper Forbes' Battery has two fine magazines, one brick and one stone, built against the cliff wall.

During the Second World War a 40-mm Mark 3 gun on a mobile mounting was placed in Upper Forbes Battery in 1942 and remained there until December 1944.

A Second World War iron cupola cantilevered out from the rock face housed a searchlight.