In the 1930s virtually all the Army's stockpile of ammunition was held at Bramley, which was vulnerable to air attack, so three new Central Ammunition Depots (CAD) were built: Serving south, central and northern England respectively, these were CAD Monkton Farleigh, Wiltshire (also known as CAD Corsham, an underground depot); CAD Nesscliffe, Shropshire; and CAD Longtown, Cumbria. By 1942 more storage capacity was required and another CAD was opened: Kineton. That same year a very large COD, widely spread out across the Oxfordshire countryside to mitigate the risk of bomb damage, opened at Bicester to hold stores principally to support the invasion of France.