Author and researcher Adrian records the trials and tribulations of staff in the UK Hydrographic Department, responsible for all the charts and navigational products designed, compiled, proofed, printed and distributed to the Allies during WWII. Their vital work was undertaken in total secrecy, and the number of charts they produced was staggering. During the war 30.7 million charts and diagrams were supplied to 4,969 vessels from 14 allied countries, compared with an average of 3.5 million over a similar period in peacetime. Presented by the Royal Scottish Geographic Society.