Mark I Tank

1. Lead

The Mark I was the first tank in history. Built in Britain in 1916, it was a huge rhomboid machine, designed to cross trenches, crush barbed wire and carry machine guns and cannon into the heart of the German defences on the Western Front.

On 15 September 1916, at Flers-Courcelette on the Somme, 49 Mark I tanks went into battle for the first time, and although many broke down and only a few reached the German lines, the effect on the soldiers who saw them was immense. The tank had arrived, and warfare would never be the same again.

About 150 Mark I tanks were built, in two versions — the “Male”, armed with cannon, and the “Female”, armed only with machine guns — and they fought on the Somme, at Arras and at Ypres before being replaced by improved designs.

The Mark I was a crude machine by later standards. It was slow, moving at walking pace, it was deafeningly loud and hot inside, and it broke down constantly. Its crew of eight worked in conditions that would be considered intolerable today, and the tank’s armour, at most 12 mm thick, could be penetrated by the German armour-piercing rifle bullet. Yet the Mark I proved the idea of the tank.

Every tank that followed — from the Mark IV tank to the M3 Stuart tank and the Tiger I — descends from this first rhomboid machine, and the Mark I’s basic layout, with its tracks running around the whole body of the vehicle, remained the standard for British heavy tanks for the rest of the First World War.

2. Key Facts

Type	Heavy tank (the first tank)
Origin	Britain
Designers	William Tritton and Walter Wilson; promoted by Ernest Swinton
Manufacturers	William Foster & Co., Lincoln; Metropolitan Carriage, Wagon and Finance Co.
In service	1916–1917
Produced	1916; about 150 built (75 Male, 75 Female)
Weight	About 28 tonnes
Length	About 9.9 m (with tail); about 8.1 m (without tail)
Width	About 4.3 m (Male, with sponsons)
Height	About 2.4 m
Crew	8 (commander, driver, two gearsmen, four gunners)
Armour	6–12 mm
Main armament (Male)	Two 6-pounder (57 mm) Hotchkiss guns; three Hotchkiss machine guns
Main armament (Female)	Five machine guns (four Vickers and one Hotchkiss)
Engine	Daimler-Knight six-cylinder petrol, 105 hp
Top speed	About 6 km/h on level ground
Range	About 38 km

3. Background and Development

The deadlock of the Western Front

By the end of 1914, the war on the Western Front had settled into a deadlock. Two lines of trenches ran from the Swiss border to the English Channel, protected by barbed wire, machine guns and artillery, and every attempt to break through them had failed at terrible cost.

The British and French armies lost hundreds of thousands of men in attacks that gained a few hundred metres of mud, and by 1915 it was clear that a new weapon was needed — a weapon that could cross no-man’s-land, crush the wire, survive machine-gun fire and carry its own guns into the enemy’s trenches.

Several men proposed such a weapon, but the man who turned the idea into a practical machine was Major Ernest Swinton, a Royal Engineers officer who had seen the Holt caterpillar tractor in action and who believed that a tractor, fitted with armour and guns, could break the deadlock.

Swinton’s idea was taken up by the Landships Committee, a small and secret body set up by the First Lord of the Admiralty, Winston Churchill, in February 1915. The committee, whose secretary was Albert Stern, asked the agricultural engineers William Foster & Co. of Lincoln to build a prototype, and the work was done by William Tritton, Foster’s managing director, and Lieutenant Walter Wilson of the Royal Naval Air Service, who designed the tracks.

The first prototype, “Little Willie”, was a small box-shaped vehicle with tracks running around its body, and it was tested in September 1915. It was too small and too slow, and it could not cross a wide trench, but it proved that the caterpillar track could carry an armoured vehicle.

The second prototype, “Mother”, was much larger and had the rhomboid shape that became the Mark I: its tracks ran around the whole body of the vehicle, so that the front of the track could climb out of a trench and the rear could push the vehicle forward.

Little Willie and Mother

Little Willie, tested at Burton Park near Lincoln in September 1915, was the first armoured tracked vehicle ever built, and it survives today at the Tank Museum in Bovington, where it is the oldest surviving tank in the world. It was a small vehicle, about 8 metres long and weighing about 14 tonnes, with a turret on top that was never fitted with a gun.

Its tracks, which ran around the body of the vehicle, were the key to its design, and they were designed by Walter Wilson, who had worked on the problem of how to make a track that would not slip or break.

Little Willie could cross a trench about 1.5 metres wide, but it could not cross the wide trenches of the Western Front, and its speed was only about 3 km/h. The Landships Committee therefore ordered a larger vehicle, and the result was Mother, which was tested at Hatfield Park in January 1916 and which became the direct prototype of the Mark I.

From Mother to the Mark I

Mother was accepted for production in February 1916, and the order was placed for 100 tanks, later increased to 150. The production vehicles, which were called the Mark I, were built by Foster’s and by the Metropolitan Carriage, Wagon and Finance Company, and they were built in secret, under the cover name “tank” — a word chosen to suggest that the vehicles were water carriers for the army in Mesopotamia.

The Mark I was built in two versions: the Male, armed with two 6-pounder guns in sponsons on the sides of the vehicle and three machine guns, and the Female, armed with five machine guns and no cannon. The Female was intended to protect the Male from German infantry, who would try to attack the tanks with grenades and machine guns, and the two versions were meant to fight together, in pairs.

The first Mark I tanks were delivered to the army in the summer of 1916, and their crews trained in secret at Elveden in Suffolk, where a full-scale replica of the German trenches had been built.

4. Design

The rhomboid shape and the tracks

The Mark I’s most distinctive feature was its rhomboid shape. The tracks ran around the whole body of the vehicle, so that the tank looked like a giant diamond on its side, and the shape was chosen for a single reason: to cross trenches.

When the Mark I approached a trench, the front of its track would drop into the trench and then climb out of the far side, while the rear of the track pushed the vehicle forward, and the long, sloping front of the track gave the tank a better chance of climbing out of a wide trench than any other shape.

The Mark I could cross a trench about 3.5 metres wide, climb a slope of about 45 degrees and crush barbed wire under its tracks, and it could cross a parapet about 1.4 metres high. The tracks were made of cast steel links, and they were driven by a Daimler engine through a gearbox that was so difficult to operate that the tank needed two men — the driver and the commander, or the driver and one of the gearsmen — to change gear.

Armour and armament

The Mark I’s armour was thin by later standards: 6 mm on the sides and rear, 10 mm on the front and 12 mm on the sponsons of the Male. It was enough to stop rifle bullets and machine-gun fire, which was the main threat on the Western Front, but it could be penetrated by the German armour-piercing rifle bullet, the “K” bullet, which was issued to German infantry in 1917 specifically to deal with tanks.

The Male’s armament was two 6-pounder (57 mm) Hotchkiss guns, mounted in sponsons on the sides of the vehicle, and three Hotchkiss machine guns, one in the front and one in each sponson. The Female’s armament was five machine guns: four Vickers and one Hotchkiss.

The guns were mounted in sponsons because the Mark I had no turret, and the sponsons gave the guns a wide field of fire to the sides and to the front, but not to the rear.

The crew and conditions inside

The Mark I’s crew of eight worked in conditions that were appalling even by the standards of the First World War. The engine was inside the fighting compartment, and it filled the tank with heat, noise, fumes and carbon monoxide.

The temperature inside the tank could reach 50 degrees Celsius, and the crew wore goggles and masks to protect themselves from the fumes and from the splinters that flew off the inside of the armour when it was hit. The tank was steered by the driver, who controlled the tracks with levers, and by two gearsmen, who worked the gearbox, and changing gear required the driver and the gearsmen to work together, which made the tank very difficult to drive.

The crew communicated by hand signals, because the noise of the engine made speech impossible, and the tank’s speed, about 6 km/h on level ground and much less across broken ground, meant that it moved at walking pace.

5. Variants

Variant	Year	Key features	Production
Mark I Male	1916	Two 6-pounder guns; three machine guns	75
Mark I Female	1916	Five machine guns; no cannon	75
Mark I with tail wheels	1916	Steering tail fitted to early vehicles; later removed	Fitted to early tanks
Mark I supply tank	1916–1917	A few Mark Is converted to carry supplies	Small numbers

Male and Female

The Mark I was built in two versions, and the difference between them was their armament. The Male carried two 6-pounder guns and three machine guns, and it was intended to destroy German machine-gun posts, strongpoints and artillery. The Female carried five machine guns and no cannon, and it was intended to protect the Male from German infantry, who would try to attack the tanks with grenades, machine guns and rifles.

The two versions were meant to fight together, in pairs, with the Female covering the Male while the Male destroyed the German defences. In practice, the distinction was soon abandoned: later tanks, above all the Mark IV tank, were built with a single armament, and the “Male” and “Female” names were dropped, although the idea of a tank armed with both cannon and machine guns survived.

The Male’s 6-pounder guns were the same Hotchkiss guns used by the Royal Navy, and they were chosen because they were available in large numbers and could be mounted in the sponsons without a major redesign.

The tail wheels and the supply tanks

The early Mark I tanks were fitted with a pair of large steering wheels at the rear, mounted on a frame that extended behind the vehicle. The tail wheels were intended to help the tank steer, and they were a survival from the design of the Holt tractor, but they proved useless in practice and were soon removed, and later Mark I tanks were built without them.

A small number of Mark I tanks were converted to supply tanks, with their sponsons removed and their interiors fitted out to carry supplies, ammunition and water to the infantry in the front line. The supply tanks were used at Cambrai in 1917 and in the battles of 1918, and they were the ancestors of the armoured supply vehicles of the Second World War.

The supply tanks carried ammunition, water and rations in their empty hulls, and they followed the fighting tanks into the captured German trenches, where the infantry were waiting for them.

6. Operational History

Flers-Courcelette, 15 September 1916

The Mark I first saw action on 15 September 1916, at Flers-Courcelette, during the Battle of the Somme. The British commander, General Haig, had been persuaded by Swinton to use the tanks, although only 49 of them were ready, and although many of the crews had had only a few weeks of training. The tanks were committed in small groups, alongside the infantry, and the result was mixed.

Of the 49 tanks, 32 reached the start line, and of those, about 9 reached the German lines. Many broke down or became stuck in the mud, and several were hit by German artillery, but those that did reach the German trenches caused panic among the German infantry, who had never seen such a machine, and they helped the British to capture the village of Flers.

The battle was a tactical success, but it was not the breakthrough that Haig had hoped for, and the tanks were withdrawn after the battle.

The tanks that reached Flers

The tanks that reached the German lines at Flers did more than capture a village: they showed what the tank could do. One tank, D17, commanded by Captain Mortimer, drove down the main street of Flers, firing its guns at the German defenders, and the German infantry fled before it.

Another tank, D5, crossed the German trenches and reached the far side, where it was eventually abandoned after it ran out of fuel. The German soldiers who saw the tanks reported that they were terrified by the machines, which seemed invulnerable to rifle fire and which crushed the wire and the trenches under their tracks.

The British press reported the battle with enthusiasm, and the tank became famous overnight, although the military value of the action was limited by the small number of tanks and by their mechanical unreliability. The German command, which had dismissed the tank as a British curiosity, ordered its engineers to study the captured machines and to begin work on anti-tank defences.

The lessons of the Somme

The Somme taught the British Army several lessons about the tank. The first was that the tank needed to be used in large numbers, and in a concentrated attack, rather than in small groups spread along the front. The second was that the tank needed better mechanical reliability, and that its crews needed more training.

The third was that the tank needed to be protected from German artillery, which was the main threat to it, and that it needed to be used in conjunction with the infantry and the artillery, rather than on its own.

These lessons were applied in the later battles of the war, above all at Cambrai in 1917, where nearly 500 tanks were used in a single attack, and the Mark I’s successors, the Mark II, Mark III and Mark IV, were designed to be more reliable and better armed than the Mark I.

The lessons also shaped the organisation of the Tank Corps, which grew from a single battalion into a corps of several brigades by the end of the war.

Arras and Ypres, 1917

After the Somme, the Mark I fought at Arras in April 1917, where it supported the British attack on the German lines, and at Ypres in the summer of 1917, where it fought in the mud of Passchendaele. At Arras, the tanks were used in larger numbers than at the Somme, and they helped the British to capture the German positions, but many broke down or became stuck in the mud, and the battle was not the breakthrough that had been hoped for.

At Ypres, the tanks were almost useless: the ground was so wet and so broken by shellfire that the tanks sank into the mud and could not move, and many were abandoned in no-man’s-land. By the end of 1917, the Mark I had been replaced by the Mark IV, which was better armoured and better armed, and the surviving Mark Is were used for training or converted to supply tanks.

7. Performance and Specifications

Specification	Mark I Male	Mark I Female
Main armament	Two 6-pounder (57 mm) guns	Five machine guns
Armour (maximum)	12 mm	12 mm
Armour (front)	10 mm	10 mm
Weight	About 28 tonnes	About 28 tonnes
Engine	Daimler-Knight, 105 hp	Daimler-Knight, 105 hp
Power-to-weight	About 3.7 hp per tonne	About 3.7 hp per tonne
Top speed	About 6 km/h	About 6 km/h
Trench crossing	About 3.5 m	About 3.5 m
Range	About 38 km	About 38 km
Crew	8	8
Number built	75	75

Firepower and protection

The Mark I’s firepower was modest, but it was enough for the task it was designed to do. The Male’s 6-pounder guns could destroy German machine-gun posts, strongpoints and field guns, and they could fire high-explosive shells against infantry and armour-piercing shells against German strongpoints. The Female’s machine guns could sweep the German trenches with fire, and they could protect the Male from German infantry.

The Mark I’s armour, at most 12 mm thick, was enough to stop rifle bullets and machine-gun fire, which was the main threat on the Western Front, but it was not enough to stop the German armour-piercing rifle bullet, and it was certainly not enough to stop German artillery.

The Mark I’s real protection was its size and its novelty: the German infantry had never seen such a machine, and they did not know how to fight it. The 6-pounder’s high-explosive shell was effective against German machine-gun nests, which were often built of concrete and sandbags, and which the tank’s guns could destroy at ranges of several hundred metres.

Mobility and reliability

The Mark I’s mobility was poor by any later standard, and its reliability was worse. Its top speed was about 6 km/h on level ground, and much less across broken ground, and its range was only about 38 km, which meant that it could not operate far from its start line.

Its engine, a Daimler-Knight petrol engine of 105 horsepower, was underpowered for a vehicle that weighed 28 tonnes, and its gearbox was so difficult to operate that the tank needed two men to change gear. The Mark I broke down constantly: at Flers, of the 49 tanks that went into battle, 17 broke down before they reached the start line, and many more broke down during the battle.

The Mark I’s tracks, which were made of cast steel links, wore out quickly, and the tank’s steering, which was done by braking one track and driving the other, was difficult and unreliable.

8. Operators

Britain: the Tank Corps

The Mark I was used only by Britain. It was issued to the Heavy Section of the Machine Gun Corps, which became the Tank Corps in July 1917, and it was the first tank of the British Army. The Tank Corps was a new arm, and its officers and men had to learn everything about the tank from scratch: how to drive it, how to maintain it, how to fight in it and how to use it in conjunction with the infantry and the artillery.

The Mark I’s crews were volunteers, and many of them were engineers, mechanics and drivers who had joined the army to work on the new machines. The Tank Corps grew rapidly, from a few hundred men in 1916 to thousands by 1918, and it became one of the most important arms of the British Army.

By 1918, the Tank Corps had grown to more than 20,000 men, and it operated hundreds of tanks in the great offensives of the last year of the war.

Captured Mark Is and the Germans

The Germans captured a number of Mark I tanks, and they studied them carefully, but they did not build a tank of their own until 1917, when they produced the A7V, of which only 20 were built. The Germans were slow to appreciate the tank, and they believed that the machine gun and the artillery were more important, and that the tank was a British curiosity that would not change the war.

They were wrong, and by 1918 the Germans were using captured British tanks, including Mark IVs, against the British, and they had begun to develop anti-tank weapons, including the armour-piercing rifle bullet and the first anti-tank gun. The Mark I’s influence on the Germans was therefore indirect: it forced them to think about how to fight tanks, and it showed them that the tank was a weapon that could not be ignored.

The Germans also copied the British idea of the tank, and their first tank, the A7V, was built in 1917, although only 20 were completed before the end of the war.

9. Legacy and Influence

The first tank

The Mark I’s legacy is that it was the first tank, and that it proved the idea of the tank. Every tank that followed descends from the Mark I, and the basic idea of the Mark I — an armoured vehicle, running on caterpillar tracks, carrying its own guns and able to cross trenches and crush wire — has remained the basis of tank design ever since.

The Mark I also established the Tank Corps, which became the Royal Tank Regiment, and it established the idea that the tank was a distinct arm, with its own doctrine, its own training and its own tactics. The Mark I’s influence on the First World War was limited by its small numbers and by its mechanical unreliability, but its influence on the history of warfare was immense.

The Mark I also proved that a new weapon could be developed in secret, in less than two years, and put into action before the enemy had time to develop a counter to it.

The tank in history and memory

The Mark I has become a symbol of the First World War, and of the British invention of the tank. The name “tank”, which was chosen as a cover name in 1915, has become the universal name for the armoured fighting vehicle, and the Mark I’s rhomboid shape has become the classic image of the First World War tank.

The Mark I is remembered in Britain as a triumph of British engineering, and as a weapon that helped to win the war, although historians have qualified that judgement: the Mark I’s contribution to the Allied victory was limited, and the tank did not become a decisive weapon until the Second World War.

The Mark I’s real importance is that it showed what was possible, and that it opened the way for the tanks that followed. Today, the Mark I is remembered in Britain as the machine that began the age of the tank, and its centenary in 2016 was marked by exhibitions, by a full-size replica and by ceremonies at Flers and at Bovington.

10. Surviving Examples

The Tank Museum, Bovington

Only a handful of Mark I tanks survive, and the best-known example is held at the Tank Museum in Bovington, England. The museum holds a Mark I Male, which was presented to the museum after the war, and which is displayed alongside the museum’s other First World War tanks, including the Mark II, Mark IV and Mark V.

The museum also holds Little Willie, the prototype that preceded the Mark I, which is the oldest surviving tank in the world. For most visitors, the easiest way to see a Mark I is at Bovington, where the museum’s First World War tanks are displayed in the order in which they were built, and where the Mark I’s rhomboid shape can be seen in full.

The museum’s Mark I is displayed with its sponsons and tail wheels intact, and visitors can walk around it and see the cramped fighting compartment through the open hatches.

Replicas and memorials

Because so few Mark I tanks survive, most people see the Mark I in the form of replicas and memorials. A full-size replica of a Mark I was built for the centenary of the Battle of the Somme in 2016, and it has been displayed at museums and at commemorative events in Britain and France.

Mark I tanks are also commemorated in the towns where they were built: Lincoln, where Foster’s built the first tanks, has a Mark IV as a memorial, and the Tank Museum at Bovington holds the world’s most important collection of First World War tanks.

The Mark I’s rhomboid shape has also been used in memorials and in public art, and it remains the most recognisable image of the First World War tank. In France, the village of Flers, where the tanks first went into action, remembers the Mark I in its local museum and in the ceremonies held each September.

Frequently Asked Questions

What is the Mark I tank?
The Mark I was the world’s first tank, built in Britain in 1916. About 150 were built, in Male and Female versions, and it first saw action at Flers-Courcelette on the Somme on 15 September 1916.

Why was it called a “tank”?
“Tank” was a cover name, chosen to suggest that the vehicles were water carriers for the army in Mesopotamia. The name stuck, and it became the universal name for the armoured fighting vehicle.

How many Mark I tanks were built?
About 150 Mark I tanks were built in 1916 — 75 Male and 75 Female — by William Foster & Co. of Lincoln and the Metropolitan Carriage, Wagon and Finance Company.

What is the difference between a Male and a Female Mark I?
The Male was armed with two 6-pounder guns and three machine guns, and the Female was armed with five machine guns and no cannon. The Female was intended to protect the Male from German infantry.

Where can I see a Mark I today?
The best-known surviving Mark I is at the Tank Museum in Bovington, England. The museum also holds Little Willie, the prototype that preceded the Mark I and the oldest surviving tank in the world.

How fast was the Mark I?
The Mark I’s top speed was about 6 km/h on level ground, and much less across broken ground. It moved at walking pace, and its range was only about 38 km.

Related articles

• 44M Tas Tank
• A-20 Havoc
• Balao-class Submarine

Sources

1. Wikipedia, “Mark I tank” — production of about 150, specifications, Flers-Courcelette and the Male/Female distinction.
2. The Tank Museum, Bovington, “Mark I” and “Little Willie” — the development of the tank and the surviving examples.
3. David Fletcher, British Mark I Tank 1916 (Osprey Publishing, 2004) — design, development and the first action.
4. Paddy Griffith, Battle Tactics of the Western Front (Yale University Press, 1994) — the tank at Flers-Courcelette and its tactical use.
5. John Glanfield, The Devil’s Chariots (Sutton Publishing, 2006) — the birth of the Tank Corps and the first tanks.
6. Tank Encyclopedia, “Mark I” — specifications, variants and surviving examples.