Since 1543, a fort has stood near Beacon Hill to protect Harwich from enemy attack. The remains of the original blockhouse are now at the far end of the stone breakwater as a result of erosion.
During the invasion scare in the 1790’s a new, three gun battery was built, but this was also replaced by 1810 due to further erosion.
By the 1840’s, with a further risk of invasion by the French, a five gun battery was installed just in front of the present day Cornwallis Battery. This battery fell into disrepair with the advent of newer guns being installed at Harwich Redoubt. These Rifle Muzzle Loaders (RML’s) were being used to fend off an attack by the new Iron Clad Battleships of the day.
By 1890, The RML’s were being replaced by more powerful guns known as Breech Loaders. These had almost twice the range of the earlier guns. Harwich Redoubt was not able to be updated, so a new battery was built nearby at Beacon Hill.
The original guns were two Elswick Disappearing Guns, one 10 inch and one 6 inch calibre with a maximum range of 4.5 miles. These were joined by two 4.7 inch Quick Firing Guns with a similar range and two 3 pounder Quick Firing Guns for local defence and practice.
By 1904, the two Disappearing guns had been replaced by two 6 inch Breech Loaders en barbette. These were able to fire over a low parapet wall and were protected by iron shields in front of the gun crew.
The fort was reused in WWI and WWII with alterations being made up until 1941 with the building of Cornwallis Battery, the last battery installed at Beacon Hill.
The fort closed in 1956 with the cessation of Coastal Defence.