Following the postponement, by Hitler, of Operation Felix in early 1941 the immediate threat of an assault on Gibraltar receded but by that time Churchill had already decided to create a fortress that could withstand a one-year siege.
At the outbreak of war in 1939 galleries that had been cut since 1903 linked all the existing gun positions on the Rock. The galleries included bombproof accommodation for 2,000 men. Between 1939 and 1945 these were extended to cater for a garrison of 10,000 men and had to include food and water supplies, electricity generation, hospitals, sanitary facilities, laundry, accommodation, cooking facilities and magazines. Provision had to be made for water and fuel reservoirs. The lack of water on Gibraltar meant rationing had to be introduced. Each man was allowed 2 gallons of fresh water per day and twenty five gallons of sea water. It was during this period that seawater soap was developed. Separate accommodation was built for females. The main galleries were built to allow lorries to travel along them and had a maximum incline of 1:8. The accommodation tunnels built off the main galleries were made large enough to take a standard Nissen hut or even, in some cases, a concrete block building with a trussed roof with in both cases at least 2 feet of air space all around. To undertake the mining work, four companies of coal and soft rock miners were formed. They worked between 1941 and 1943 accompanied by a Canadian tunnelling company who used diamond-drilling techniques; unknown technology to the British miners. Between 1943 and the end of the war in 1945 one company continued the work. Work did not stop in 1945 although the majority of tunnels had been constructed by then. The last tunnel to be completed was Molesend Way in 1968. There are now 34 miles, (54 kilometres) of tunnels inside Gibraltar.
In 2005 a short stretch of these tunnels was opened to the public. The entrance is at Hays Level between the Moorish Castle and the 18th century Siege Tunnels. The guided tour takes about one hour.
Due to the constant monitoring by German spies of activity on the Rock throughout the war as much of the work as possible had to be conducted in secret and disposal of the spoil from the mining was a major concern. Working day and night the accumulated spoil of the day was used to provide a foundation for the runway. The daily carry of spoil and quarried scree was 7,500 tons.
In October 1941 the first plans for an airfield had been drawn. They specified a runway initially 1,150 yards long and 150 yards wide. This entailed building into the sea for a distance of 570 yards. Incredibly the work was completed by April 1942. The runway then had to be extended to 1,550 yards to accommodate the aircraft that would be used during Operation Torch, the allied invasion of North Africa that took place in November 1942 and, by early 1943 to a full length of 1,800 yards.
As most people know the defences of Gibraltar were never put to the ultimate test and, despite the Germans carefully watching all the activity on the Rock, they never fully realised the extent of the defences. By the end of the war for instance, Gibraltar, tiny by comparison, had more searchlight batteries and more anti-aircraft guns than the city of London. Today the Germans have finally discovered all. My guide through the tunnels was a cheerful German called Hans who not only had a wicked sense of humour but freely admitted that the information he had now would have been invaluable to his side during the war.
© Nicholas Craig Nutter 2004 - 2012. Nick Nutter asserts his rights as the author of this article and all associated images. This article and images may not be copied or reproduced in any way without written permission of the author.