Vickers Medium Mark I
The Vickers Medium Mark I was a British tank
A tank is a tracked, armoured fighting vehicle designed for front-line combat which combines operational mobility, tactical offensive, and defensive capabilities...

 of the period between the two World Wars built by Vickers
Vickers was a famous name in British engineering that existed through many companies from 1828 until 1999.-Early history:Vickers was formed in Sheffield as a steel foundry by the miller Edward Vickers and his father-in-law George Naylor in 1828. Naylor was a partner in the foundry Naylor &...



After the First World War Britain disbanded most of its tank units: their number was limited to five tank battalions, equipped with the Mark V and the Medium Mark C
Medium Mark C
The Medium Mark C Hornet was a British tank developed during the First World War, but produced too late to see any fighting.-Development:In 1917 Sir William Tritton had developed the Medium Mark A Whippet without involving his former co-worker Walter Gordon Wilson. In response Major Wilson began to...

. A large budget was at first made available for tank design; this was however all spent on the failed development of the Medium Mark D. When in 1923 the government design bureau, the Tank Design Department, was closed, for the time being any direct official involvement in tank development was terminated. But private enterprise had already taken over the torch. Vickers-Armstrong had built two prototypes of a new tank in 1921.

Vickers Light Tank

In 1920 the Infantry had plans to acquire a Light Infantry Tank. Colonel Johnson of the Tank Design Department derived such a type from the Medium Mark D. In competition Vickers built the Vickers Light Tank.

The Vickers design still was reminiscent of the Great War types. It had a high, lozenge-shaped, track frame with side doors but it also showed some improvements. There was a fully revolving turret and the suspension was sprung by vertical helical springs, while the Medium Mark C still had a fixed turret and was unsprung. The Vickers was really a light tank; it was small vehicle, just seven feet high and weighing only 8.5 short tons. It was driven by a separately compartmented 86 hp
Horsepower is the name of several units of measurement of power. The most common definitions equal between 735.5 and 750 watts.Horsepower was originally defined to compare the output of steam engines with the power of draft horses in continuous operation. The unit was widely adopted to measure the...

 engine through an advanced hydraulic Williams-Jenney transmission, allowing infinitely variable turn cycles. The first prototype was a "Female" version with three Hotchkiss machine gun
Hotchkiss machine gun
Hotchkiss machine gun:*Hotchkiss M1909, light machine gun also known as the "Hotchkiss Mark I" in British service*Hotchkiss M1914, medium machine gun*Hotchkiss M1922, light machine gun*13.2 mm Hotchkiss machine gun, heavy machine gun...

s; the second prototype was "Male", its turret bristling with armament with the addition of a 3-pounder gun and a machine gun for anti-aircraft use. It had clearly been intended to give the vehicle a modern look: the turret, the front of the fighting compartment and the hull front plate were all strongly rounded. The advanced transmission proved to be utterly unreliable however and the project was abandoned in 1922 in favour of a generally more conventional design: the Vickers Light Tank Mark I, that would be renamed to Vickers Medium Tank Mark I in 1924 . The first prototypes were sent to Bovington for trial in 1923. The Vickers designation was A2E1.


Despite being in general more conventional, in one aspect the Medium Mark I looked rather modern: instead of a high track run it possessed a low and flat suspension system with five bogies, each having a pair of small double wheels. The axles of these were too weakly constructed; as Major-General N.W. Duncan put it in his Medium Marks I-III: "(...) a perpetual nuisance. The axles were continuously breaking and the path of the Mark I tanks was littered with discarded wheels". To ease repairs the suspension was not protected by an armoured covering. There were two vertical helical springs of unequal length in each of the five bogie casings attached to the hull. In front and behind the normal ten road wheel pairs, there was a tension wheel pair. Ground pressure was very high, even though at 11.7 long tons the vehicle was not very heavy for its size.


All this was driven by an air-cooled 90 hp Armstrong Siddeley
Armstrong Siddeley
Armstrong Siddeley was a British engineering group that operated during the first half of the 20th century. It was formed in 1919 and is best known for the production of luxury motor cars and aircraft engines.-Siddeley Autocars:...

 engine derived from an aircraft type. Surprisingly the hull was uncompartimentalised with the engine to the left of the driver, which Duncan laments as "an unbelievable retrograde step in view of war-time experience". The Medium Mark B
Medium Mark B
The Medium Mark B was a British tank of the First World War developed as a successor to the Whippet, but ultimately unsatisfactory and production was cancelled at the end of the war.-History:...

 and the Mark VIII
Mark VIII (tank)
The Tank Mark VIII or Liberty was an Anglo-American tank design of the First World War. Initially intended to be a collaborative effort to equip France, the UK and the US with a single tank design, it did not come to fruition before the end of the war and only a few were produced.-Early...

 had introduced compartmentalisation to reduce the debilitating effects of engine noise and fumes on the crew. However with the Medium Mark I considerations of ease of maintenance had taken precedence.


The engine drove, via a multiple dry-plate clutch, a four-speed gearbox. It had no synchromesh and switching between gears without making it sound as if the entire vehicle was about to come apart, apparently posed a bit of a challenge to the driver. A propeller shaft connected the gearbox to a bevel box at the end of the tank which divided the power to a separate epicyclic gear for each track. These gears automatically provided extra emergency torsion to the normal first and second gear if the vehicle suddenly slowed down due to an obstacle or soft ground.

Fuel and oil

The petrol tanks were on top of them, so the fuel ducts had to run along the whole length of the vehicle, pumping fuel to a secondary tank that fed the engine by gravity. The engine was cooled and lubricated by oil; leakage was common and the original four-gallon reservoir had to be replaced by a 13.5 one. The tank could be electrically started, but only if the motor was already warm, so the first start had to be done by hand from the inside of the vehicle. Maximum speed was about 15 mph and the range about 120 miles.


There was a cylindrical bevelled turret on top of the hull that carried a "Quick Firing" three-pounder gun (47 mm calibre) and four ball mountings for Hotchkiss machine guns.
A novel, unique feature was a three-man turret. This meant that commander was not distracted with neither loader's or gunner's tasks and could fully concentrate on maintaining situational awareness. This gave a huge potential combat advantage, but went largely unnoticed at the time. Non-Vickers tanks did not have this capability until the German Panzer III
Panzer III
Panzer III was the common name of a medium tank that was developed in the 1930s by Germany and was used extensively in World War II. The official German designation was Panzerkampfwagen III translating as "armoured battle vehicle". It was intended to fight other armoured fighting vehicles and...

 was developed in 1937. The practical importance of this feature is signified by the fact that later into the World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

, most of both sides tanks' designs either quickly switched to the three-man turret, or were abandoned as obsolete.

There was no co-axial machine gun. There was only room to operate one machine gun from the turret; normally one gun was switched between the respective mountings as the guns were removable. The turret machine gunner doubled as main gun loader. In each side of the hull was a Vickers machine gun, but there was only one gunner, also functioning as mechanic.


The shape of the Mark I Medium hull was very distinctive. The back was a simple armoured box; the front plate was high and perfectly vertical. Between them, from the armoured hood of the driver at the right of the vehicle six armour plates fanned out to the left, making for a complex hull geometry at that side. In all the tank made an ungainly squat impression. The crew of five was only poorly protected by 6.25 mm plating, rivetted to the chassis, barely enough to counter the threat posed by light machine guns. With its many shot traps the vehicle was unable to withstand even anti-tank rifle
Anti-tank rifle
An anti-tank rifle is a rifle designed to penetrate the armour of vehicles, particularly tanks. The usefulness of rifles for this purpose ran from the introduction of tanks in World War I and until the Korean War...

 fire and it had a high profile. The internal lay-out worsened this vulnerability as the petrol tanks were inside the main compartment.

Operational history

The Medium Mark I replaced some of the Mark V heavy tanks; together with its successor, the slightly improved Vickers Medium Mark II
Vickers Medium Mark II
The Vickers Medium Mark II was a British tank built by Vickers in the Inter-war period.The Medium Mark II, derived from the Vickers Medium Mark I, was developed to replace the last of the Medium Mark Cs still in use. Production and rebuilding ran from 1925 until 1934. The tank was phased out of...

, it served in the Royal Tank Regiment
Royal Tank Regiment
The Royal Tank Regiment is an armoured regiment of the British Army. It was formerly known as the Tank Corps and the Royal Tank Corps. It is part of the Royal Armoured Corps and is made up of two operational regiments, the 1st Royal Tank Regiment and the 2nd Royal Tank Regiment...

s, being the first type of the in total 200 tanks to be phased out in 1938.

The Medium Mark I was the first tank to see "mass" production since the last of the ten Char 2C
Char 2C
The Char 2C was a French super-heavy tank developed, although never deployed, during World War I. It was the largest operational tank ever.-Development:...

's had been finished in 1921. Indeed, as of the next tank, the Renault NC27, only about thirty were built, the British Mediums represented most of the world tank production during the Twenties. They never fired a shot in anger and their performance in a real battle can only be speculated upon but as the only modern tanks in existence in the decade after the First World War they provided the British with a unique opportunity to test the many new ideas about mechanised warfare
Mechanized Warfare
Mechanized Warfare is the sixth studio album released by American power metal band Jag Panzer, released in 2001. This album is more progressive than the band's previous work...

 using real operational units. The knowledge thus gained would prove invaluable in the Second World War


  • Medium Mark I: first type of which thirty were built from 1924 onwards.
  • Medium Mark IA: fifty were built of a slightly improved type with 8 mm armour at the vertical surfaces, a split diver's hood, a bevelled back plate of the turret to facilitate anit-aircraft fire and improved brow and chin pads for the gunners. The Mark IA's could be started from the outside. The troublesome bogies were replaced on all eighty tanks by a stronger type.
  • Medium Mark IA*: the original tank turrets were rebuilt and upgraded by removing the Hotchkiss mountings, installing a co-axial Vickers machine gun
    Vickers machine gun
    Not to be confused with the Vickers light machine gunThe Vickers machine gun or Vickers gun is a name primarily used to refer to the water-cooled .303 inch machine gun produced by Vickers Limited, originally for the British Army...

    , compensating its weight by a lead counterweight at the back of the turret and putting the Bishops's Mitre on top of it, a traversable cupola
    In architecture, a cupola is a small, most-often dome-like, structure on top of a building. Often used to provide a lookout or to admit light and air, it usually crowns a larger roof or dome....

  • Medium Mark I CS and Medium Mark IA CS: a dozen tanks were rebuilt as close support vehicles, mainly for smoke laying, equipped with a 15-pounder mortar.
  • Experimental Wheel and Track Medium Mark I: this was a wheel-cum-track project of 1926 to improve strategic mobility. The tank could be elevated by jacks on four enormous rubber-tyred wheels, two to be lowered at its extremes, the front ones steerable. The back ones could be driven, making the vehicle look "rather like a house perched on a very inadequate roller skate"; more practical was to tow it by a truck. This vehicle was also equipped with an experimental driver's hood. The contraption was later removed.

On one Medium Mark I the engine was replaced by a Ricardo
Ricardo is the Portuguese and Spanish cognate of the name Richard. Therefore the name means "Brave Ruler".-People with the first name Ricardo:*Ricardo Arona, Brazilian mixed martial artist*Ricardo de Araújo Pereira, Portuguese comedian...

90 hp diesel engine.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.