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<font color="white" face="Geneva,Arial" size="2">Hay's Level is the starting point of the GUIDED WALKING TOUR of the Second World War and 18th Century Tunnels.</font>
<p><font color="white" face="Geneva,Arial" size="2">The greatest, single British military tunnelling project carried out by army personnel is the tunnelling in Gibraltar during World War Two, when diamond-drill blasting was used by the army for the first time.</font></p>
<p><font color="white" face="Geneva,Arial" size="2">The Hay's Level entrance is one of many entrance and exit points leading into over 30 miles of interconnected tunnels. Most of the system is still under M.o.D. jurisdiction, however, a significant amount can be visited, such as this WW2 and 18th Century section.</font></p>
<p><font color="white" face="Geneva,Arial" size="2">This series of parallel chambers is named Fordhams Accommodation after Colonel H M Fordham OBE, MC, Chief Engineer 1940-41. The chambers were constructed by enlarging the original Liddell Union Tunnel which extends southward to the Calpe Hospital chambers.</font></p>
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<p><font color="white" face="Geneva,Arial" size="2">The purpose of the WW2 tunnelling project in Gibraltar was to provide accommodation sufficient to enable the garrison to live underground and resist a siege for a period of up to a year. Such accommodation, therefore, had to include provision for water supply, electric light and power, sanitary arrangements, hospital and laundry in addition to the normal accommodation of personnel.</font></p>
<p><font color="white" face="Geneva,Arial" size="2">Chambers were cut to allow the erection of buildings which were either standard army hutting or buildings constructed of concrete block walls and normal roof trusses. The panorama opposite and photograph above shows a nissen hut in position within the chamber. Frosted glass windows helped the occupants feel a sense of normality despite being deep beneath ground.</font></p>
<p><font color="white" face="Geneva,Arial" size="2">In all chambers two feet of clear air space all round the building was allowed. This space was essential so that water seeping through the rock could drain away through the drainage channels provided; it also permitted air circulation around the buildings, and facilitated periodic inspection of the rock face.</font></p>
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<p><font color="white" face="Geneva,Arial" size="2">Every chamber having a span of more than 12ft was arched, the rise being one fifth of the span. In the early days. spans up to 3Sft had been cut with flat roofs, but these gave endless trouble from rock falls, particularly when further excavations were being carried out in the vicinity. One of the largest chambers, 380ft long x SOft span, was given an 11 ft rise of arch and was very successful.</font></p>
<p><font color="white" face="Geneva,Arial" size="2">In planning economically, the aim was to reduce the access tunnelling to the minimum. Chambers leading directly off the main tunnel, were generally used, with a passing bay provided to avoid congestion or, even better, with a service tunnel.</font></p>
<p><font color="white" face="Geneva,Arial" size="2">The chambers were generally 28ft to 40ft span, and 150ft to 200ft long, and in every case were connected at their ends by a small section tunnel called a 'back drive'. Such connection was essential to allow for the circulation of air, and to assist in keeping the chambers fresh. Cul-de-sac chambers would be damp and almost unusable for any purpose.</font></p>
<p><font color="white" face="Geneva,Arial" size="2">Chambers were also cut parallel to the main tunnel as this assisted the internal planning considerably by avoiding long passages but occupied long frontages of the main tunnels and was wasteful.</font></p>
<p><font color="white" face="Geneva,Arial" size="2">A pillar of rock. 20ft to 30ft wide was allowed between each chamber and, where one system was being developed above another, a clear rock space of 100ft between the two systems was considered the minimum safe thickness. Small communication tunnels, however, up to 12ft span, were crossed with only 18ft between the roof of the lower tunnel and the floor of the higher. In planning the tunnelling, it had to be remembered that it would be difficult to provide future extensions in the immediate vicinity, because the subsequent blasting would have damaged the chambers already fitted out. It was essential, therefore, to make full provision at the start, even though some of the chambers could not be fitted out at once.</font></p>
<p><font color="white" face="Geneva,Arial" size="2">Tunnelling companies were formed for the work in Gibraltar, mainly from coal miners and soft- rock miners and, from 1941 to 1943, four companies were in operation on the Rock together with a Canadian tunnelling company with a diamond-drill detachment. From 1943 to 1945, one company remained to continue the work. Gibraltar rock is a bedded limestone accumulated on fairly shallow banks. It is hard and of reasonable uniformity, although there are faults and variations which, in tunnelling, had to be taken into account. Areas of shattered and broken rock had to be avoided but it was the general uniformity which made possible accurate cutting of chambers by diamond-drill blasting (period photographs courtesy of the Imperial War Museum).</font></p>
<p><font color="white" face="Geneva,Arial" size="2">This junction of tunnels provides access to other major systems of tunnels within the Rock, hence the reference to one of England's major railway hubs. This tongue-in-cheek army humour with place names actually helped British personnel become familiar with the tunnel systems quickly.</font></p>
<p><font color="white" face="Geneva,Arial" size="2">The passage to the right of Liddell's Union leads to the remains of Willis's Engine Room and adjacent Mess.</font></p>
<p><font color="white" face="Geneva,Arial" size="2">In the panorama opposite you can see the fantastic view from this observation position cut into the sheer north face of the Rock. The airfield, frontier, La Linea can be clearly seen. The public cemetery is in the foreground at the foot of the Rock.</font></p>
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<p><font color="white" face="Geneva,Arial" size="2">Constructed in 1941 by the 4th Battalion, Black Watch who were part of the garrison from July 1940 until April 1943. Their work parties were engaged on the construction of much of the tunnelled defences in the North face end of the accommodation chambers which they occupied.</font></p>
<p><font color="white" face="Geneva,Arial" size="2">The balcony is accessed from Clapham Junction via a series of blast traps.</font></p>
<p><font color="white" face="Geneva,Arial" size="2">The panorama opposite shows the junction where the WW2 tunnelling meets Willis's Gallery of 1789. The doorway to the surface leads out onto Willis's Plateau on which Princess Anne's Battery is located.</font></p>
<p><font color="white" face="Geneva,Arial" size="2">Princess Anne's Battery is the only intact battery of 5.25 inch AA guns anywhere in the world. Unfortunately the guns have suffered from the weather and vandalism over the years and although they were repainted in 2004 further maintenance is required to stop any further deterioration.</font>
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