§ Mr. Simmondsasked the Minister for the Co-ordination of Defence the thickness of concrete necessary to prevent the penetration of every known type of aerial bomb?
§ Sir T. InskipBombs may weigh as much as 2,000 lbs. and thicknesses of reinforced concrete of 20 feet or more would probably be required to provide complete protection against them. A 500 lb. semi-armour piercing bomb may, however, be regarded as a common type of heavy bomb, such as might be employed against important targets: and if this is taken as a standard, I am informed that the thickness of reinforced concrete required to resist the penetration and explosive effects of a heavy high explosive bomb is of the order of 15 feet.