World War I
Modern armoured warfare began during the First World War of 1914-1918. Strategists wanted to break the tactical, operational and strategic stalemates forced on commanders on the Western Front by the effectiveness of entrenched defensive infantry armed with machine guns—known as trench warfare. Under these conditions, attacks usually advanced very slowly and incurred massive casualties. The developers of tanks aimed to return manoeuvre to warfare, and found a practical way to do so: providing caterpillar traction to (machine-)guns (allowing them to overcome trenches) while at the same time offering them armour protection against small-arms (rifle, machine gun) fire as they were moving.
British heavy tank of World War I
Britain and France first developed tanks in 1915 as a way of navigating the barbed wire and other obstacles of no-man's land while remaining protected from machine-gun fire. British Mark I tanks first went into action at the Somme on 15 September 1916, but did not manage to break the deadlock of trench warfare. The first French employment of tanks, on 16 April 1917, using the Schneider CA, also failed to live up to expectations. In the Battle of Cambrai (1917) (November to December 1917) British tanks were more successful, and broke a German trenchline system, the Hindenburg Line.
Despite the generally unpromising beginnings, the military and political leadership in both Britain and France during 1917 backed large investment into armoured-vehicle production. This led to a sharp increase in the number of available tanks for 1918. The German Empire, on the contrary, produced only a few tanks, late in the war. Twenty German A7V tanks were produced during the entire conflict, compared to over 4,400 French and over 2,500 British tanks of various kinds. Nonetheless, World War I saw the first tank-versus-tank battle, during the Second Battle of Villers-Bretonneux in April 1918, when a group of three German A7V tanks engaged a group of three British Mark IV tanks which they met accidentally.
After the final German Spring Offensives of 21 March to 18 July, 1918, the Entente deployed tanks en masse at the Battle of Soissons (18 to 22 July 1918) and Battle of Amiens (August 1918), which ended the stalemate imposed by trench warfare on the Western Front, and thus effectively ended the war.
Tactically, deployment plans for armour during the war typically placed a strong emphasis on direct support for infantry. The tank's main tasks were seenflank enemy lines. In practice, tank warfare during most of World War I was hampered by the technical immaturity of the new weapon system, causing mechanical failure, limited production-numbers, general underutilisation, low speeds and a short range.
as crushing barbed-wire and destroying machine-gun nests, facilitating the advance of foot soldiers. Theoretical debate largely focused on the question of whether to use a "swarm" of light tanks for this, or a limited number of potent heavy vehicles. Though in the Battle of Cambrai a large concentration of British heavy tanks effected a breakthrough, it was not exploited by armour. The manoeuvrability of the tank should at least in theory regain armies the ability to
Strategic use of tanks developed only slowly during and immediately after World War I, partly due to these technical limitations but also due to the prestige role traditionally accorded to horse-mounted cavalry. An exception, on paper, was the Plan 1919 of the British Army's Colonel John Fuller, who envisaged using the expected vast increase in armour production during 1919 to execute deep strategic penetrations by mechanised forces consisting of tanks and infantry carried by lorries, supported by aeroplanes, to paralyse the enemy command-structure.
Following the First World War, the technical and doctrinal aspects of armoured warfare became more sophisticated and diverged into multiple schools of doctrinal thought.