The initial plan was to drop the notes over Britain to bring about a collapse of the British economy during the Second World War. The first phase was run from early 1940 by the Sicherheitsdienst (SD) under the title Unternehmen Andreas (Operation Andreas, Operation Andrew). The unit successfully duplicated the rag paper used by the British, produced near-identical engraving blocks and deduced the algorithm used to create the alpha-numeric serial code on each note.