British heavy tanks of World War I

British Mark I tank with the Solomon camouflage scheme

• Crew: 8
• Combat Weight
• 31.4 tons (28.4 tonnes)
• Armour: 0.23–0.47 in (6–12 mm)
• Armament
• two 6-pounder QF, three Hotchkiss Machine Guns

The Gun Carrier Mark I was a separate design, intended to carry a field gun or howitzer that could be fired from the vehicle. In service, it was mostly used for carrying supplies and ammunition. Forty-eight of them were built.

Initial production of the Mark I was to be by Fosters and Metropolitan: 25 from Fosters and 75 from Metropolitan, which had greater capacity in Wednesbury at the Old Park site of the Patent Shaft Company, a subsidiary of the Metropolitan.[18] Metropolitan also received an order for a further 50 so that the Army would be able to raise six tank companies of 25 tanks each and set up further production under their Oldbury Wagon and Carriage Company. As there were not enough 6-pounder guns available for all 150 tanks, it was decided to equip half of them with just machine guns. A new sponson design with two Vickers machine guns in rotating shields was produced.[19]

Later in the war when newer tanks came into use some Mark Is were converted to be used for carrying supplies. A few Female Mark Is were used as mobile wireless stations by installation of a wireless transmitter. The radio could only be operated once the tank had stopped and erected a very tall mast that carried the aerial array.[20]

Mark II; tank no. 799 captured near Arras on 11 April 1917

The Mark II incorporated minor improvements over the Mark I. With the Army declaring the Mark I still insufficiently developed for use, the Mark II (for which orders were first placed in July) would continue to be built, but would be used only for training.[17] Due to this intended role, they were supposedly clad in unhardened steel, though some doubt was cast on this claim in early 1917.[21] Initially, 20 were shipped to France and 25 remained at the training ground at Wool, Dorset in Britain; the remaining five were kept for use as test vehicles. As the promised Mark IV tanks had not arrived by early 1917, it was decided, despite the protestations of Stern (see below), to ship the 25 training vehicles in Britain to France,[21] where they joined the other 20 Mark IIs and 15 Mark Is at the Battle of Arras in April 1917. The Germans were able to pierce the armour of both the Mark I and Mark II tanks at Arras with their armour-piercing machine gun ammunition.

The Mark II was built from December 1916 to January 1917 by Foster & Co and Metropolitan (25 Male and 25 Female respectively).[22]

Five Mark IIs were taken for experiments on improved powerplants and transmission. They were provided to firms to show what improvements they could make over the Mark I system in an open competition. In the demonstrations held in March 1917, only three of them were able to compete alongside Mother, which had been fitted with a Daimler petrol-electric system. Wilson's epicyclic gear system, which replaced the secondary gear and the gearsmen, was clearly superior and adopted in later designs.

Mark III tank in a ditch, in 1917

The Mark III was a training tank and used Lewis machine guns and a smaller sponson for the females. Fifty were built. It was originally intended that the Mark III was to have all the proposed new design features of the Mark IV. This is why there were two distinct training types, the Mark II being little more than a slightly improved Mark I. However, development of the new features was so slow that the change from the Mark II was very gradual. The last two Mark IIIs were melted down in the Second World War. They did not see action overseas.

A female Mark IV tank C14. Photographed with German forces after the Battle of Cambrai. December 1917

The Mark IV was a more heavily armoured version of the Mark I, and went into production in May 1917. Fundamental mechanical improvements had originally been intended, but had to be postponed. The main change was the introduction of shorter-barrelled 6-pounder guns. It had all its fuel stored in a single external tank (located between the rear track horns) in an attempt to improve crew safety. The sponsons could be swung in on hinges to reduce the width of the tank for rail transportation (previous models required partial disassembly to fit within the loading gauge). Rails on the roof carried an unditching beam. A total of 1,220 were built: 420 males, 595 females and 205 tank tenders, which were supply tanks.

The Mark IVs were used successfully at the Messines Ridge in June 1917, where they outpaced the infantry on dry ground, but in the Third Ypres of July and August they found the swampy ground difficult and were of little use. About 432 Mark IV tanks were used during the Battle of Cambrai in November 1917.

The first tank-to-tank battle was between Mk IV tanks and German A7Vs in the Second Battle of Villers-Bretonneux in April 1918.[lower-alpha 1]

Mark V "male" tank, showing short 6-pounder (57-mm) Hotchkiss gun in right sponson

A Mark V* tank—on the roof, the tank carries an unditching beam on rails, that could be attached to the tracks and used to extricate itself from difficult muddy trenches and shell craters

A Mark V** tank

The Mark V was first intended to be a completely new design of tank, of which a wooden mock-up had been finished. However, when the new engine and transmission originally destined for the Mark IV became available in December 1917, the first, more advanced Mark V design was abandoned for fear of disrupting the production run. The designation "Mark V" was switched to an improved version of the Mark IV, not equipped with the new systems. The original design of the Mark IV was to be a large improvement on the Mark III but had been scaled back to be a mild improvement because of technical delays. The Mark V thus turned out very similar to the original design of the Mark IV – i.e. a greatly modified Mark III.

Four hundred were built, two hundred each of Males and Females. Several were converted to Hermaphrodites (also known as "Composites") by fitting one male and one female sponson so that each tank had a 6-pounder. This measure was intended to ensure that female tanks would not be outgunned when faced with captured British male tanks in German use or the Germans' own A7V.

The Mark V was first used in the Battle of Hamel on 4 July 1918, when 60 tanks contributed to a successful assault on the German lines by Australian units. It took part in eight further major engagements during the War. A number saw service in the Allied intervention in the Russian Civil War on the White Russian side. Most were captured and used by the Red Army in the Russian Civil War. Four were retained by Estonian forces, and two by Latvia.

The Mark V* was a version with a stretched hull, lengthening it by 6 ft (1.8 m). It had a larger cupola on the roof and doors in the side of the hull (previous versions had small hatches under the sponsons of females or small doors in the rear of the sponson for males, along with a small hatch in the rear). The extra section was also designed to house a squad of infantry. The weight was 33 tons. Of orders for 500 Males and 200 Females, 579 had been built by the Armistice – the order was completed by Metropolitan Carriage in March 1919.[23]

Because the Mark V* had been lengthened, its original length-width ratio had been spoiled. Lateral forces in a turn now became unacceptably high, causing thrown tracks and an enormous turn circle. Therefore, Major Wilson redesigned the track in May 1918, with a stronger curve to the lower run reducing ground contact and the tracks widened to 26.5 in (673 mm). The Mark V engine was bored out to give 225 hp (168 kW) and was sat further back in the hull. The cabin for the driver was combined with the commander's cabin; there now was a separate machine gun position in the back. Of a revised order for 700 tanks (150 Females and 550 Males), only 25 were built and only one of those by the end of 1918.[23]

Wooden mockup of the proposed Mark VI, 1917

The Mark VI was one of a pair of related projects to develop the tank initiated in late 1916. The Mark V would be the application of as many advanced features as could be managed on the Mark I hull design and the Mark VI would be a complete break with the Mark I hull. The Mark V would not be built as such, because of the delays with the Mark IV and it would be a different Mark V that was built. The Mark VI project design had a completely new hull – taller and with rounded track paths. The single main gun was in the front of the hull. It did not progress past the stage of a wooden mock-up; the project was cancelled in December 1917 in order that a tank co-developed with the US (the Mark VIII) could go forward.

Mark VII tank

Mark Knothe, the Technical Liaison Officer between Stern, Elles and Anley, contributed to the development of the tank, designing a longer Mark I with Williams-Janney hydraulic transmission;[24] one of the Mark IIs used as test vehicles had used a hydraulic transmission. In October 1917 Brown Brothers[lower-alpha 2] in Edinburgh were granted a contract to develop this line of research further. In July 1918, the prototype was ready. Its drive system was very complex. The 150 hp (112 kW) Ricardo engine drove into Variable Speed Gear Ltd. pumps that in turn powered two hydraulic motors, moving one track each by means of several chains. To ward off the obvious danger of overheating, there were many fans, louvres and radiators. However, steering was easy and gradual and the version was taken into production to equip one tank battalion. Three had been built, and only one delivered out of an order for 74 when war ended.[24] It was passed over in favour over the VIII, which was ordered at the same time. The hull was slightly lengthened in comparison with the Mark V. No Mark VIIs survive.

The Allied Mark VIII (Liberty) tank

When Stern was removed from his post following disagreements with the War Office, he was sidelined by appointment to a new department to work on a cooperative design between the Allies – assembly in France, hulls, guns and their ammunition from the UK and other components (principally the engines) from the USA.[25] American involvement in the development of the tank design led to the Mark VIII, also known as "Liberty" or Anglo-American tank (though initially the French were partially involved).

The engine was compartmentalised from the crew, and the cupola structure included forward and rear firing machine guns. Of a planned (shared production) of 1,500 each, a single British prototype was finished by the end of the war. The British built just 24, the Americans completed 100 between September 1918 and 1920, at the Rock Island Arsenal, at a cost of $35,000 [£8,750] apiece ($430,000 [£226,000] in 2006). About 40 hulls for the U.S Liberty were produced by the Manchester Tank Syndicate, 11 British Type Mark VIII by the North British Locomotive Co.[26]

They were used and upgraded until the 1930s, when they were given to Canada for training; some M1917s were sold to the Canadians at nominal scrap value. The tank itself was over 34 feet (10 m) long, and there had been an even longer 44-foot (13 m) version planned but never made (the Mark VIII*). The tank was outdated by the 1930s due to its speed (under 6 mph/10 km/h) and armour (16–6 mm), but it did have one of the longest independent trench crossing capabilities of any armoured fighting vehicle (AFV) ever made. Modern main battle tanks and AFVs rely on bridge laying tanks for crossing large deep trenches.

• Crew: 12 (later 10)
• Weight 37 tons (37.6 tonnes)
• Length/Height/Width : 34 ft 2 in by 10 ft 3 in by 12 ft 4 in (10.4 m by 3.1 m by 3.8 m) (Mark VIII* length 44 ft/13.4 m)
• Engine: Ricardo 330 hp (250 kW) petrol (UK), Liberty V12 300 hp (220 kW) (U.S.).[26]

Mark IX tank

The Mark IX was a troop carrier or infantry supply vehicle – among the first tracked armoured personnel carriers not counting experiments with the lengthened Mk Vs. Thirty-four were built out of an order for 200.

The Mark X was a paper-only project to improve the Mark V, originally known as Mark V***. This was basically a contingency plan in case the Mark VIII project failed (if so a production of 2000 was foreseen for 1919), trying to produce a tank with as many parts of the Mark V as possible but with improved manoeuvrability and crew comfort.

Little Willie showing its rear steering wheels, September 1915

Little Willie survives at the Bovington Tank Museum. It was saved from being scrapped in 1940 on the pretext that it was helping to defend Bovington base against possible German attacks. Many other prototypes were melted down during the invasion scare.

The original Mark I Tank C19, Clan Leslie

A single male survives. This is the only surviving Mark I and the world's oldest surviving combat tank. It is part of the collection at the Bovington Tank Museum. It is painted to represent Number 705, C19, Clan Leslie although its identity and wartime history are unknown. There are indications that it may have served as a driver-training tank and it has been suggested it is Number 702, which would make it the second Mark I built. Between 1919 and 1970, it was sited in the grounds of Hatfield House to commemorate the fact this was a testing site for tanks during their earliest development.[32]

The Bovington Mark II tank, F53 The Flying Scotsman

There is a single more or less complete surviving Mark II, F53: The Flying Scotsman, at the Bovington Tank Museum (see below). This tank still has battle damage sustained at the Battle of Arras in April 1917. This vehicle was originally a Male, had been rebuilt as a supply vehicle, was restored and for a time displayed as a Mark I with a Female barbette on the right side, and was later shown as a Mark II.

Surviving parts from Mark II no. 799 (D26), including tracks and gunshields, can be seen at the Musée Jean et Denise Letaille, Bullecourt.

Seven Mark IVs survive.

• A Mark IV Female is at the Museum of Lincolnshire Life, Lincoln, England, on permanent loan from the Bovington Tank Museum. A local company, William Foster & Co., manufactured the first tanks. The tank is an empty shell that, at some point in its history, was stripped of its internal components. It is painted as F4: Flirt II, which fought at the Battle of Cambrai and was subsequently captured by the Germans. While there is some evidence the Lincolnshire tank may indeed be Flirt II, its history prior to the Second World War is uncertain.[33]
• A Mark IV Female is preserved at Ashford in Kent. This is one of many that were presented for display to towns and cities in Britain after the war; most were scrapped in the 1920s and 1930s.
• The Royal Museum of the Army in Brussels has a Male Mark IV tank, the Lodestar III, still in original colours.
• A Mark IV Female, Grit, is stored at the Australian War Memorial. It was on display in ANZAC Hall at the Australian War Memorial until August 2008. It is now kept at their bulk store in Mitchell, Canberra.[34]
• In 1999, a Mark IV Female, D51: Deborah, was excavated at the village of Flesquières in France. It had been knocked out by shell-fire at the Battle of Cambrai (1917) and subsequently buried when used to fill a crater. Work is underway on its restoration.[35]
• A Mark IV Male, Excellent, is displayed at Bovington. After World War I, this tank was presented by the army to HMS Excellent, a Royal Navy shore establishment where some tank crewmen were trained. During World War II, it was made operational again for service with the Home Guard when German invasion threatened in 1940.[36] It is still maintained in working order.[37]
• Mark IV Female Liberty: displayed at United States Army Ordnance Museum, Aberdeen, Maryland. Originally named Britannia, Renamed Liberty, the tank joined the Ordnance Museum collection in 1919. After decades of exposure to the elements, it is in poor condition, but about to undergo restoration.[38]

Mark V 9199 at The Tank Museum at Bovington (2015). This tank is maintained in working order but is no longer run, in order to help preserve it.

Eleven Mark Vs survive. The majority are in Russia or Ukraine and are survivors of the tanks sent there to aid the White forces during the Russian Civil War.

• The Tank Museum, Bovington displays a Mark V Male, Number 9199, one of two British World War I tanks still in working order. It was in action at the Battle of Amiens where its commander – Lt. H. A. Whittenbury – was awarded the Military Cross. This tank is maintained in running condition, but is no longer run because of the wear and tear that would be inflicted on the now-fragile, historic vehicle.[31]
• A Mark V** Female: Ol' Faithful, is also preserved at Bovington.
• A heavily restored Mark V Male, Devil, survives at the London Imperial War Museum.
• A Mark V* Male, Number 9591, has since 2010 been part of the collection of the National Armor and Cavalry Museum, Fort Benning, Georgia. It was issued to Company A, US 301st Heavy Tank Battalion, and knocked out by a single artillery round on 27 September 1918, during the attack against the Hindenburg Line. It was repaired and sent back to the United States, and is the only surviving example of the Mark V*.
• A Mark V is at the Kubinka Tank Museum, Russia.
• A Mark V serves as memorial in Arkhangelsk. This was originally used by British forces during the Allied Intervention in the Russian Civil War.
• Two preserved Mark Vs, a Male and a Female, form part of an outdoor memorial at Luhansk in Ukraine; two more are in storage.
• A Mark V Female is at the M. F. Sumtsov Kharkiv Historical Museum, Ukraine.

• A Mark VIII Liberty tank originally at the Aberdeen Proving Ground, Maryland, has in 2010 been transferred to the National Armor and Cavalry Museum at Fort Benning, GA. The vehicle was originally assigned to the American 67th Infantry Regiment (Heavy Tanks) at Fort Benning, GA.
• A Liberty tank is preserved at Fort Meade, Maryland. The tank displayed in the post museum was made in 1920 at Rock Island Arsenal, Illinois. It was assigned to the 301st Tank Battalion (Heavy), later redesignated the 17th Tank Battalion (Heavy). Throughout most of 1921–1922, Major Dwight D. Eisenhower commanded this unit.
• A British Mark VIII is at Bovington.

A single restored vehicle survives at Bovington.