In 1859, in response to the threat of invasion by Louis Napoleon (Napoleon III), a granite gun battery was built on the Island, to cover Porthmeor and the approach to the harbour. The fortification extended west from Lamp Rock, a rocky outcrop on the north-east corner of the Island. That name originated in the days when it was the site of a lantern to guide local fishing boats into Porthgwidden cove (before St Ives had the harbour), or a warning beacon if enemy ships were sighted.
It consisted of three gun emplacements. The northernmost was higher than the others, and had a larger gun, in order to cover the landward approach to the town. The ammunition was stored in a cellar beneath the gun emplacements. During a test firing the large gun fired a 68lb cannonball, which landed close to the rock target c. 1500 yards away. However, the shots from the two smaller guns fell short. One ball rebounded from a rock back onto the Island and exploded close to cows grazing on the meadow!
The building at the western end of the gun emplacements was the barracks, to house the gunners and their families. At that time the building had rifle slits instead of windows, for defence in case of invasion (until recently the building was used as an artist’s studio).
In 1887, the weaponry was upgraded to three 64-pounders. However, in 1895, it was decided that, as St Ives was only a fishing village, it did not need defences, so the battery was dismantled and the guns and stores were removed to Devonport. In about 1905, the Admiralty erected a signalling mast and a semaphore pole within the emplacements, on what was then referred to as ‘Battery Point’.
Forty years later, a lookout station was built within the largest of the gun emplacements. It was manned night and day by local coastguards, working under their commanding officer and based in the Coastguard Station and cottages above Porthminster. The Coastguard station was closed down in 1994, when the government decided that the use of satellite and wireless technology to monitor distress calls made a visual watch unnecessary.
In 1999, it was reopened by the St Ives branch of the National Coastwatch Institution, leasing it from the local council. It is now manned by volunteer watchkeepers, all year round during daylight hours, keeping a log of all the activity within sight of the lookout.