RAF Harpur Hill
…in the country across the 500 acres (200 ha) site. During World War I, Frith artillery range was located on the site. In 1938 the Air Ministry bought Harpur Hill Quarry from ICI. A total of 11 tunnels were built (concrete galleries covered by waste quarry stones) and dug into the hillside from 1938 to 1940 by McAlpine…