Admiral Lord West tells the story of the Royal Navy during the 20th century, when through political, social, technological and economic turmoil, the Navy's fortunes mirrored those of Britain. Lord West begins on the beaches of northern France, introducing the series through the greatest amphibious assault in history - D-Day, a turning point in naval warfare. From there, he goes back in history to discuss 'navalism' at the start of the 20th century.

The Navy in the decade before the First World War was vast, a truly globalised organisation, defending British interests around the world. At home it was the bulwark against invasion and had such a powerful hold on the British imagination that images of sailors - of Jack Tar - sold everything from cigarettes to postcards. And it was a powerful political force too, with crowds following naval developments closely and, when the pace of warship production seemed to be slackening, demanding more. This was an era when political meetings were interrupted with chants of 'Dreadnought! Dreadnought! Dreadnought!' But for all its size and strength, the Royal Navy at the dawn of the 20th century had rot at its core - social stagnation and a rules-based mentality were stifling the fighting spirit that had characterised Nelson's navy.

Reform would come only with two titans of the era - Winston Churchill and, first, Admiral 'Jacky' Fisher.

Naval history in fifteen parts Producer: Giles Edwards

First broadcast on BBC Radio 4 in June 2014.