Source and copyright
Source: The mushroom cloud generated during Britain's first hydrogen bomb test as seen from an aircraft flying above the local natural cloud on 15 May 1957. The weapon was dropped high over Malden Island in the Central Pacific by a Royal Air Force Valiant bomber [online]. BRITAIN'S NUCLEAR TEST PROGRAMME: OPERATION GRAPPLE. Part of CENTRAL OFFICE OF INFORMATION POST 1945 OFFICIAL PUBLIC RELATIONS COLLECTION. Ministry of Supply official photographer. London: Imperial War Museum. Black and White. © IWM (GOV 9111) Catalogue number GOV 9111.
Available at: http://www.iwm.org.uk/collections/item/object/205189628.
Copyright: (c) Imperial War Museum