Trench warfare
Trench warfare has become archetypically associated with the First World War of 1914–1918, when the Race to the Sea rapidly expanded trench use on the Western Front starting in September 1914. By the end of October 1914 the whole front in Belgium and France had solidified into lines of trenches, which lasted until the last weeks of the war. Mass infantry assaults were futile in the face of artillery fire as well as rapid rifle and machine-gun fire. Both sides concentrated on breaking up enemy attacks and on protecting their own troops by digging deep into the ground. Trench warfare also took place on other fronts, including in Italy and at Gallipoli.
Cecil Vandepeer Clarke
When production of the limpet mine was under way, Clarke started work on a radical and ambitious project. Drawing on his experiences of trench warfare in the First World War and his particular expertise in tunnelling and explosives, he drew up a proposal for an armoured trench-forming machine. Although the war had started, there was little real fighting on the Western Front and this period became known as the Phoney War. However, Clarke reasoned that eventually Germany's much vaunted "Siegfried Line" must be attacked. His trench-forming machine would drive through the earth advancing 2000 yards in a single night, men and tanks following in its wake in the relative safety of the trench it had formed.