He was of the opinion that if he could raise a tower on this south summit of the Rock, he would be able to observe the coming and goings of the enemy at Cadiz harbour, over sixty miles away. His tower easy built but was unsuccessful, and was named O’Hara’s Folly by the garrison. It survived until 1888 when discussion about it’s imminent demolition made it the subject of a wager between the garrison gunners and the gunnery officers of HMS Wasp. The end result was that Wasp used spars and rigging to enable her guns to bear at a high elevation and commenced blasting away at the tower. Shot 6 cracked it from top to bottom… and off they sailed, honour satisfied.

The first 6” gun was mounted in 1890, but it was replaced in 1901 by a 9.2 with a range of 29,000 yards, helped somewhat by it’s height above sea level. It was last fired in 1976 and won’t be fired again.

If this gun and Lord Airey’s had never been subjected to sustained firing it is likely that they would dismounted themselves, as the ridge of rock on which they stand is insufficient to absorb the tremendous shock-loads imposed by these ferocious weapons.