The idea of a tracked armored fighting vehicle was first put into practical military use by the British Admiralty. In fact, it was through Winston Churchill's direction - then the First Lord of the Admiralty and future British Prime Minister - that the tank, as a weapon of war, initially came to be. The world entered World War 1 in the summer of 1914 and the war quickly came to a stalemate within a matter of months - the Western Front brought to a halt by the bloody engagements that stemmed from trench warfare. To help break the stalemate, many weapons were improvised throughout the conflict and these endeavors ultimately gave rise to the fighter aircraft, the bomber aircraft, the flamethrower and - of course- the "tank" as we know it today. In February of 1915, Churchill assembled several thinkers through the "Landships Committee" with the goal of formalizing the idea of an armored and armed tracked land vehicle - thusly the name "landship" was accordingly associated with these early combat systems. The name "landship" was akin to the "battleship" of the navy - then the most powerful surface vessel devised. The landship would, therefore, be its equivalent on land. The word "tank" was originally formulated as a cover for landship development - "tank" being used to disguise the true nature of the vehicle and intended to give prying eyes the impression of industrial-type water tanks being developed.
The group took to studying the concept of the armored vehicle in the context of the ongoing war - a war that had devolved from fluid in its nature to static at many fronts. The vehicle was initially considered as a troop transport that could break through the various battlefield obstacles such as barbed wire fences, trenches (up to 5 feet wide) and artillery craters and bring combat-ready soldiers closer to the fight under relative security. Additionally, the vehicle could be armed with machine guns which would allow it to engage enemy machine gunners and infantry in turn. In essence, the design would become the world's first true infantry fighting vehicle.
Based on the chassis of peacetime farming tractors and heavy movers, the idea gained steam in various circles of thought. Within time, a prototype armored vehicle was rolled out by Fosters of Lincoln in 1916 quickly becoming the first-ever armored vehicle prototype in history. This particular 18-ton vehicle was completed with a turret (though non-rotating in the prototype) emplacement covered over in boiler plate armor and fitted over a tracked chassis. Overall height was 10 feet tall with a running length of 18 feet and width of 9 feet, 4 inches. The exterior was utilitarian at best - a bench for the two drivers - while the exterior sported a crude riveted appearance with featureless surfaces and a rudimentary tracked wheeled system. Steering was assisted via a two-wheeled attachment installed at the rear of the vehicle - to function as a ships rudder of sorts - though more responsive steering, it was found, could be accomplished by simply braking one track side and running the other forward. The British Army evaluated this prototype in the early part of 1916.
It was intended that the vehicle - now known as "Little Willie" - would be armed capably with a 2-pdr (40mm) field gun. Additionally, provision for a .303 caliber (7.7mm) machine gun was also added with the option of mounting additional machine gun positions as needed to cover the various "blindspots" of the primary armament. Crew accommodations began with two standard personnel (for steering and braking) but this rose to six total to help manage the various weapon stations.
When Little Willie was ultimately tested it was quickly realized that the vehicle could not capably maneuver the trenches as required. Additionally, its overall speed of 2 miles per hour made it slower than infantry components on foot, especially over uneven terrain. The landship maneuvered poorly in mud and was thinly armored with its boiler plate skin. The various vertical surfaces also presented various "shot trap" areas which would have furthered endangered the crew. It was only in her internals and underlying structure that the Little Willie truly evolved armored warfare to a feasible level - her automotive components were eventually refined and adopted in future British tank designs of the war. The development process learned in creating the Little Willie certainly helped to lay down the foundation for the various "Mk" series tanks to follow for the "Big Willie" (also known as "Mother") was already in manufacture by the end of September 1916. From there, the landship would go on to form the armored spearhead of the Allied response to the Central Powers territorial holds in France and Belgium. Within time, the Central Powers would be demoralized and ultimately defeated, forced to sue for peace which was eventually marked by the November 1918 Armistice. There is no doubt that the appearance of armored tracked vehicles in the numbers provided gave a tremendous advantage to the Allies in the war. Interestingly, the tables would be turned in World War 2 with the German initiative concerning armored warfare.
At any rate, the Little Willie ushered in the concept of armored warfare first and brought a whole new world of strategic thinking to a battlefield that relied on fluid mobility of men, cavalry and cannon just 100 years prior (the Napoleonic Era being the primary example of this). Only a single Little Willie prototype was ever completed and this very specimen can be seen in its preserved form at the Bovington Tank Museum in Southwest England.