United Kingdom (1938)
Airborne Light Tank – 100 built

At the start of the 20th century, nations at war experienced rapid technological advancement, and with this development came a time of adaptation and experimentation. The end of the Great War saw many countries taking stock of what had been introduced and experienced, and the interwar period proved to be a time of rapid development, testing, and theorizing, of which armored vehicles were no exception. The British Army saw fit to change the makeup of their forces to accommodate new tanks and therefore broke the vehicle design into three groups; light tanks, cruiser tanks, and infantry tanks.

Infantry tanks were designed to provide armored support for infantry units, so speed was not a focus. The Royal Tank Corps, and the Cavalry Corps however, both requested faster Armored Fighting Vehicles (AFV) to fill the roles of rapid breakthrough exploitation and reconnaissance. These ‘cruiser tanks’ were used as mechanized cavalry, utilizing lighter arms, and lighter armor than infantry tanks. The final category, light tanks, were designed to scout enemy positions, and act as policing vehicles for occupational forces, and as such, they consisted of minimal armor, and usually were only armed with machine guns. The Vickers-Armstrongs’ series of light tanks proved popular for the British Army.

As a result, British and Commonwealth nations used the Vickers-Armstrongs Light Tank Mk VI extensively from the mid to late 1930’s. Due to its popularity, the Mk.VI was still in operational use at the start of World War II, however, chief tank designer Leslie Little was working on a private project to replace the Mk.VI, which would form the basis for the new Mark. VII Tetrarch. The name ‘Tetrarch’ is the Roman title given to the governor of one of four provinces of territory, or the Greek word for ‘ruler’.)


Tetrarch light tank at the Armoured Fighting Vehicle School, Gunnery Wing at Lulworth in Dorset, 25th of March 1943. Source: Imperial War Museum Collection

Development

When the British Expeditionary Force was deployed in Europe from 1939 to 1940, a majority of the armor available consisted of the Mk.VI. However, the Vickers-Armstrong company was developing the Light Tank Mk.VII. Starting the design in 1937, and proposed to the War Office in 1938, the “Purdah” (meaning a state of seclusion or secrecy) tank as it was nicknamed, was sent to trials by 1938. Originally, the Mk. VII was put through trials designed to test its viability as a ‘light cruiser’ tank, since the British Army was still satisfied with the Mk.VI at the time, and felt that it did not need to be replaced. Eventually, though the Mk.VII was rejected for the light cruiser role, in favor of the Cruiser Tank Mk. I, A9.


Prototype Tetrarch from the factory. Note the odd muzzle break on the main weapon, and the Vickers machine gun cowling.

Trials for the Mk.VII lasted from May until June 1938, and at their completion, the War Office assigned the Mk VII a new ordnance designation; ‘A.17.’ An order was put in for a limited run of 70 Mk. VII to be built in July but the number was raised to 120 in November with two required design changes. First, the armament would be changed from a 15mm Besa main gun, and a 7.92mm Besa machine gun to an Ordnance Quick-Firing 2-pounder (40mm) gun with a coaxial 7.92mm Besa. A second requirement specified the for mounting of an external fuel tank on the rear of the vehicle to increase the operational range. In July of 1940, production started on the Mk. VII, but the War Office soon reduced the requested number of Mk. VII’s to the July 1938 number of 70, before raising it again to 100 and finally to 220.

Production

After the Mk.VII was approved for production by the War Office, the use of light tanks encountered several obstacles. In 1940, the Battle of France was ongoing, and the Vickers Mk.VI, which was better suited for light security duties, fared poorly in combat against German armor and many of the Mk.VIs were abandoned after the Battle of Dunkirk. British tank production began to focus on infantry and cruiser tanks, phasing out light tanks. Vickers production slowed due to a transfer of the Mk.VII from the plant at Elswick, Newcastle-Upon-Tyne, to the Metro-Cammell factory in Birmingham mid-1940. This was further exacerbated by Luftwaffe raids, which resulted in damaged supply lines, and also by the vehicle’s design flaws, such as a faulty cooling system. These factors pushed back the first production example to November 1940, with around 100 Mk.VIIs being produced through 1942, according to War Office documentation. These 100 tanks were given registration numbers, T.9266 to T.9365. Other sources place the number as high as 177, but this number has not been proven in official documents. In September 1941, the Mk.VII was then given the name “Tetrarch”.


General Sir Alan Brooke inspects a Tetrarch at the Army Staff College at Camberley, 6th of January 1941. Source: Imperial War Museum Collection

Design

When the Mk.VII Tetrarch was initially designed, it was meant as an upgrade to the existing Vickers Mk.VI. The armor thickness was increased to a maximum of 16mm using riveted plating, and the Henry Meadows Ltd. Type 30 twelve-cylinder engine produced up to 165 hp. The Mk.VII rode on the Christie suspension system, which used long coil springs, and the tracks utilized four road wheels, which due to their size, also acted as supports for the track return. In addition, the Mk.VII also adopted the steering mechanism used by the Universal Carriers. Turning the tank was accomplished by warping or bending the tracks from side to side, in the direction desired, providing a turning radius of around 90 feet (27.4 meters), so for tighter turns track braking was still necessary. At 7.6 tons, the Mk.VII was capable of reaching travel speeds around 64km/h (40mph).

As with most scout tanks, the crew of three worked in tight quarters, with the commander and the gunner in the turret, flanking the driver. Due to the small number crew members, it fell to the commander to fill the role of loader. By 1944 the tanks were also upgraded with a 40mm Quick Firing 2 pounder, and some received Littlejohn adaptors, increasing the velocity and trajectory of the armor piercing composite non-rigid (APCNR) rounds fired. By using the APCNR, which had a softer metal on the outside, the slightly smaller Littlejohn adaptor would compress the round, provide some resistance, and increase the pressure behind the shot. The resulting velocity would increase from 853 m/s to 1,143 m/s, giving the 2pdr the ability to penetrate about 80mm of armor from about 150m.


Pictured here is the Tetrarch with a Littlejohn adapter fitted to the end of its barrel. The vehicle also has some small rubber flaps hanging from the front. Source: Imperial War Museum Collection

Variants

Despite the troubled production sequence of the Mk.VII, and the initial lack of support from the British Army in regards to its use, two variants of the Mk.VII were produced. The first was designated the Tetrarch I CS. With this variant, the 2-pounder was replaced with a 3-inch howitzer but otherwise was mostly unchanged. The second variant was the Tetrarch DD. This version mounted a Duplex Drive and canvas screens to enable flotation and water crossings. Trials were carried out in June of 1941 with the Tetrarch in the Brent Reservoir, as it was the lightest tank available to the British Army. Due to its success, the Duplex Drive was modified for mounting on Valentine tanks, and eventually M4 Medium tanks used during Normandy.


Fitted with the experimental flotation screen, Tetrarchs were the first British tanks tested for amphibious landings. Source: British National Archives

Mk.VII Tetrarch
Standard issue Tetrarch Light Tank.Tetrarch CS (Close Fire)
Tetrarch with Littlejohn adapter fitted to the muzzle of the 2-Pounder main armament.Mark VII Tetrarch fitted with the Littlejohn adapter
Tetrarch CS (Close Support), infantry fire-support variant fitted with a 3-Inch (76mm) Howitzer.All three illustrations are by Tank Encyclopedia’s own David Bocquelet.

Operational History

The first groups to receive Tetrarch Mk.VIIs were the 1st Armoured Division and the 6th Armoured Division, but when these divisions were sent to the North African Campaign, the Tetrarchs were deemed unfit for service, due to faulty cooling systems, and never shipped with the divisions. The next British use came in 1941, in which twelve Tetrarchs were withdrawn from the 1st Armoured Division, and assigned to ‘C’ Squadron of the Special Service Squadrons. Six of these Tetrarchs were deployed to Freetown, West Africa. On the 5th of May 1942, with the start of Operation Ironclad in Madagascar, six ‘B’ Squadron Valentine tanks and six ‘C’ Squadron Tetrarchs were deployed as part of the amphibious assault at the port of Antsirane. Due to 75mm artillery emplacements and entrenched Vichy forces, the attacking British forces suffered the loss of four Valentines and three Tetrarchs, but eventually the objective was taken. By the end of the operation, only three of the twelve Tetrarchs were in running condition, and they remained stationed in Madagascar until 1943.


Tetrarch exiting a Hamilcar glider. Source: British National Archives

In 1940, the War Office and the British Army expressed a desire for airborne units to have access to heavier weaponry through the use of gliders. In January of 1941, the Tetrarch tank was paired with the General Aircraft Hamilcar, and three years later, training exercises began. Due to its success, the Tetrarch was re-designated as an airborne tank. On the 5th of June 1944, advance elements of the 5th Parachute Brigade landed and cleared the landing zone of anti-glider obstacles, so that the squadrons of the 6th Airborne Armoured Reconnaissance Regiment (AARR) could land on D-Day. Of the twenty tanks that took off for Normandy, one slipped free of its restraints and caused the glider to crash, two tanks collided upon landing, and another was hit by a landing Hamilcar glider. Eleven of the Tetrarchs also became entangled in the discarded parachutes, which took considerable time for them to be freed.

These delays in freeing the equipment, and the reorganization of airborne forces saved the Tetrarchs from having to engage the counter-attacking Kampfgruppe, ‘Von Luck,’ which contained Panzer IV’s. The next day, the Tetrarchs were ordered to move to Bois de Bavent, and reconnoiter Troarn-Caen. After linking up with the 8th Parachute Battalion in Bois de Bavent, they proceeded to assist with the British advance on Normandy, providing reconnaissance for the troops. The first area they scouted was Escoville, where they engaged enemy infantry and gun emplacements, but they were forced to rely on infantry support to engage German armor. For the remainder of the operation, the AARR was used to assist in infantry reconnaissance or to relieve troops under fire so that they could be effectively replaced by fresh soldiers. On the 31st of July, the 6th AARR was placed under the control of the 5th Parachute Brigade, and used as a rapid reaction force, and were instructed to assist with minor pushes before the breakout in August. Eventually, the Tetrarchs were relegated to HQ roles, while ‘A’ Squadron of the 6th AARR began using Cromwells. The 6th AARR was withdrawn from mainland Europe in early September, with casualties totaling 10 KIA, 32 wounded, and 10 MIA, out of the 118 deployed. This would be the final time the Tetrarchs saw combat.

Soviet Service

In June 1941, due to the start of Operation Barbarossa, the USSR was added to Britain’s Lend-Lease program. While the Lend-Lease was originally started as a method for the United States to provide aid, the British government also participated in giving aid and planned to send a fraction of the produced Tetrarchs to the USSR. Twenty tanks were delivered on the 27th of December 1941 in Zanjan, Iran, but no further deliveries were made. After crews were trained in their use, the tanks were transferred to the 151st Tank Brigade, and were used alongside the Soviet T-26. They fit into Soviet tank doctrine, who still used light tanks for scouting and combat roles, and eventually, they saw combat when the 151st Tank Brigade was under the command of the 47th Army on the Transcaucasian Front. During fighting near the Abin River on the 27th of January 1943, the 151st experienced fifteen bailouts (the crew abandoning the tank after it was hit) in their attempt to take a hill. By the 31st of January, only fourteen tanks were still operational, and on the next day of fighting, another six were lost. Even after recovery efforts, on the 1st of February 1943, the 47th Army had only nine working Tetrarchs, and by May, only seven remained running. Due to a lack of spare materials for repairs, the number continued to dwindle as the remaining tanks were transferred to the 132nd Tank Regiment and the 5th Guards Tank Brigade. By September, only two Tetrarchs remained, and they were retired in the autumn of 1943.


Tetrarchs in use by the 21st Training Tank Regiment in Shahumyan, Armenia. March 1942. Source: warspot.ru


Tetrarchs donated to the USSR pose for the camera alongside T-34 tanks in the Caucus mountains, 1942. Notice the infantrymen riding on the Tetrarchs. Source: As taken from WorldWarPhotos.info

Legacy

The invasion of Normandy was the last time the Tetrarchs were used in combat, however, they were not disbanded until around 1950. Declared obsolete in January 1946, their role as an airborne tank was gradually replaced by the M22 Locust, which was adopted by the British armed forces in 1943, relegating the Tetrarch to training roles for their remaining four years with the 3rd Hussars. Despite the short service life of the Tetrarch and the problems which occurred during development, it still secured a unique place in history for itself. The use of light tanks in airborne operations proved the versatility of armored vehicles and paved the path for future air transportable tanks. To this day, tanks are still airlifted and dropped off in hard to access locations on the battlefield and enable rapid deployment of armor to many different environments, an idea pioneered by the Light Tank Mk.VII.

Tetrarch specifications

Dimensions (L-W-H) 13′ 6” x 7′ 7” x 6′ 11” (4.11 m x 2.31 m x2.12 m)
Total weight 16,800 pounds (7,600 kg)
Crew 3 (Commander, gunner, driver)
Propulsion Henry Meadows Ltd. Type 30 twelve cylinder engine, producing 165 hp
Speed (road) 19 km/h (11.8 mph)
Armament Ordnance QF 2-pounder (40mm) gun (or 3 in (76.2 mm) howitzer)
1 x 7.92mm BESA machine gun
Armor 4 to 16 mm
Total production 6 Prototypes
For information about abbreviations check the Lexical Index

Links, Resources & Further Reading

Chamberlain, Peter; Ellis, Chris (2001). British and American Tanks of World War Two: The Complete Illustrated History of British, American, and Commonwealth Tanks 1933–1945. Cassell & Company. ISBN 0-7110-2898-2.
Fletcher, David (1989). Universal Tank: British Armour in the Second World War – Part 2. HMSO. ISBN 0-11-290534-X.
Flint, Keith (2006). Airborne Armour: Tetrarch, Locust, Hamilcar and the 6th Airborne Armoured Reconnaissance Regiment 1938–1950. Helion & Company. ISBN 1-874622-37-X.
Pasholok, Yuri. The Hard Fate of a Light Tank. READ HERE
Ware, Pat. (2011).British Tanks: The Second World War: Rare Photographs from Wartime Archives. Barnsley, South Yorkshire: Pen & Sword Military, ISBN 2:00281436.
Williams, Anthony G. (1999). The Vickers 40mm Class S Gun with Littlejohn Adaptor. The Cartridge Researcher: European Cartridge Research Association, http://www.quarryhs.co.uk/sgun.htm

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5 Responses to Tetrarch, Light Tank Mk. VII

  1. Landon says:

    It appears that the first illustration of the Tetrarch MK.VII , appears to show a gun of larger caliber than a QF-2 pounder. The gun looks like it my be a QF-3 pounder, yet this gun would have been long out of date by the time the Tetrarch entered service. I am curious if such a gun was ever fitted to a Tetrarch.

    • David.B says:

      The first one was made long ago, and indeed compared to the two other it seems thicker, whereas it should be exactly like a thinner QF-2 pdr shown by the second reference. I hope to correct it soon. Thanks for noticing.

  2. Ben Hooper says:

    my Favourite Tank

  3. Adam Cooper says:

    The operational history section closes with the line “…and the final time light tanks would be used in an airborne role in WWII.” Surely is isn’t correct as M22 Locust was used in an airborne role during the Rhine crossings in 1945.

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