Facilities included a telephone exchange, a generating station, a water desalination plant, a hospital, a frozen food store, a bakery, ammunition magazines, a vast Royal Electrical and Mechanical Engineers (REME) shed where damaged vehicles and equipment could be repaired and roads.

[2] The tunnel starts at Maida Vale behind the old Casino at Europa Road and travels north behind the Rock Hotel to Brigade Headquarters and Doncaster Adit.

It was an apt celebration as the Royal Engineers can trace their history back to the Soldier Artificer Company which was formed on the Rock to dig Gibraltar’s first tunnels during its Great Siege.

[3] Guided tours can be arranged to view the remains of the World War II installations such as the kitchens, Nissen huts, the abandoned generating station and anti-submarine nets which would have been used to close off Gibraltar Harbour to protect the Allied ships berthed there.

[1] The approximately two-hour tour normally starts at Maida Vale, at an entrance behind the old casino on Europa Road, and proceeds through several large chambers visiting Brigade Headquarters and continues for almost 1 mile (1.6 km) arriving at the Calpe Hole Generating Station.