The labyrinth of tunnels inside the Rock of Gibraltar formally known as"the Upper Galleries", is perhaps the most ingenious defence system devised by man.

At the end of the Great Siege in 1783, the defeated Commander of the French and Spanish troops, the Duc de Crillon, on being shown the fortifications that had led to the defeat of his troops commented, "These works are worthy of the Romans". This comment highlights the ingenuity of those men who, against all odds endured the onslaught of the advancing forces and were still able to devise a unique system of defence which afforded them victory.

It was during the war of American Independence, when France and Spain made an all out attempt to recapture the Rock from the British in Gibraltar's 14th Siege, recorded as the Great Siege, which lasted from July 1779 to February 1783. The Governor, General Elliot (later called Baron Heathfield of Gibraltar) is said to have offered a reward to anyone who could tell him how to get guns onto a projection from the precipitous northern face of the Rock known as the 'Notch'.

Sergeant Major Ince, a member of the Company of Soldier Artificers, forerunners of the Royal Engineers, suggested that this could be done by tunnelling through the Rock. Permission was granted, and Ince started work under the direction of Lieutenant J Eveliegh, a Royal Engineer, Aide de Camp to the Governor, on May 25th, 1782.

The tunnellers relied on the strength of their arms, on their skills with a sledgehammer and a crowbar, and were also aided with gunpowder for blasting. In five weeks 18 men had driven a tunnel 8 square feet (2.4sq m) by 82 feet long (25m) into the Rock. It is interesting to compare this with the record of a fully mechanised tunnelling company in Gibraltar during World War II, who in a week advanced 180 feet (55m).

Originally there was no intention of mounting guns in this gallery, but as the work progressed the fumes from repeated blasting almost suffocated the miners, so it was decided to open a vent to let air into the tunnel. Almost at once it was realised what an excellent embrasure this would make for a gun, so one was mounted without waiting to reach the 'Notch'.

Other embrasures were cut and guns mounted, and by the time the Siege ended in February 1783, the tunnel was 370 feet (113m) long and had four guns mounted in it. This first gallery was called 'Windsor Gallery'. Sergeant Major Ince did not stop there - he went on to tunnel two other galleries called "King's And Queen's Lines" lower down the north face of the Rock.

Work did not stop with the end of the Siege, but instead of continuing straight towards the 'Notch', a tunnel was driven downwards and a large chamber opened under the 'Notch' called St George's Hall, where a battery of seven guns where installed. The Cornwallis Chamber was also excavated at this time.

In gratitude to Sergeant Major Ince, he was given a Commission and granted a plot of land on the Upper Rock still known as Ince's Farm. In addition, the Duke of Kent (Gibraltar's Royal Governor and father of Queen Victoria) presented him with a valuable horse.

The entrance to the Upper Galleries is dominated by a Victorian 64-pounder cannon. There are other Victorian guns in the Gallery dating back to 1850, as well as an original 18th Century cannon.

The Holyland Tunnel, named as such because the tunnel points due East in the precise direction of Mecca, leads from St George's Hall to the area above Catalan Bay on the East Side of the Rock and affords magnificent views of the Mediterranean Sea. This is just a small part of a network of tunnels inside the Rock of Gibraltar.

During the Second World War, the Royal Engineers (originally the Artificer Company during the Great Siege) along with a Canadian contingent added some 30 miles (40Km) of tunnels.

The Great Siege Tunnels have been brought to life with the installation of various exhibitions within its chambers re-enacting some scenes lived in these tunnels throughout their unique history.

If the Corps of Royal Engineers had not been formed in Gibraltar, there would possibly have been no tunnels excavated.

The original company of Soldier Artificers, as proposed by Edward Cornwallis in 1771, was to consist of one Sergeant Major - Sergeant Major Ince, three Sergeants, two Corporals, three drummers and 60 Privates.

It is interesting to note that their wages ranged from 15p a day for the Sergeant Major down to 4p per day for Privates. That made Sergeant Major Ince's weekly salary �1.05 and a normal Private's salary �0.28 a week!