Mark I Tank (UK)

The Mark I Tank was the first tank to enter combat, on the Somme late in 1916. Although it was a primitive design, difficult to control and unreliable, it demonstrated that the idea had great potential, and was the basis of the improved Mark IV Tank, which played a major role in the battles of late 1917 and 1918.


Serious work on producing an armoured tracked fighting vehicle began early in 1915, after the formation of the Admiralty Landship Committee. This committee examined a number of designs for fighting vehicles, including some using tracks and some using large wheels. On 22 July 1915 Fosters of Lincoln were given a contract to produce the prototype of a tracked landship using an imported Bullock Commercial tracked unit. This vehicle was originally know as the Lincoln Machine No.1 and later as Little Willie. In its original configuration it had a simple box shaped fuselage, with a mock-up turret on top and the Bullock tracks low on either side. However the Bullock tracks were unsatisfactory, and the overall design looked unlikely to provide the trench crossing abilities required.

Luckily Major Walter G. Wilson, a pre-war automobile engineer who was working as Admiralty Overseer to the project quickly recognised the limits of the first machine, and on 17 August, only six days after work began on the prototype, suggested the layout of a more advanced machine. This second design had much longer tracks that ran all the way around the body of the vehicle to give it the required trench crossing and climbing abilities.  William Tritton for Fosters came up with a successful design for tank tracks, which were tested on the Lincoln Machine, which became known as Little Willie in its new configuration. The new design was soon approved, and work began on it in October 1915. The second prototype, generally known as ‘Mother’, was complete in January 1916 and performed in front of official audiences on 2 February. Haig’s staff were impressed, and on 12 February placed an order for 100 machines.


The Mark I Tank had the classic rhomboid shape associated with British tanks of the First World War. It was built around a long, narrow box shaped fuselage, given extra width by the track frames on either side. The tracks extended in front of and behind the main body of the tank, and these extensions were known at horns. The tracks were raised up at the front to allow the tank to climb over parapets.

The Mark I needed a crew of eight. This was made up of the driver, commander, two gunners, two loaders and two gearsmen (see the article on Mother for details of how she was controlled). The Mark I was powered by a 105hp Daimler engine, mounted almost in the centre of the fighting compartment.

Power went to the main gearbox then to the massive differential which filled up the rear of the tank. Power from the differential went sideways to secondary two speed gear boxes installed in the track frames, just behind the sponsons. Roller chains connected these gear boxes to the rear drive wheels. The original purpose of these extra gear boxes was to give a wider range of gears for the heavier tanks, but they also proved to be useful for steering.

Mark II (Female) Heavy Tank from the left Mark II (Female) Heavy Tank from the left

The Mark I used the same basic design as Mother, but was protected by 6-12mm thick armour instead of the boiler plate used on Mother. It also had a raised cupola at the front of the hull for the commander and driver.

The main armament was carried in removable sponsons on each side of the hull. Two versions were produced.

The Male was armed with two 6-pounder guns, one in the front of each sponson, and three machine guns. It was intended to attack enemy guns and fortifications. One machine gun was carried in the front of the vehicle and could be fired by the commander or driver. The other two were in the rear of the sponsons, and were to be fired by the loader.

The Female was armed with five machine guns, and had slightly larger sponsons. Each sponson carried two Vickers machine guns in circular mounts. The fifth gun was in the front, as on the Male. It was intended for use against enemy infantry and to protect the Males. The two types thus needed the same number of crewmen. The Vickers was a bulky gun, and the original female sponson only had a very small entry hatch, making it almost impossible to get out of a damaged Female Mark I in combat.

The Mark I kept the rear steering wheels of Mother, but these were unsuccessful in combat and were removed from November 1916 onwards.

In order to defend against grenades the Mark I carried a bomb-roof, made up of chicken wire attached to a wooded frame that looked like the frame of a simple shed roof.

The Mark I was followed by two orders for training tanks - the Mark II and Mark III, which were very similar but made from boilerplate instead of armoured plate and the Mark IV, which was the main tank of 1917. It wasn't until the appearance of the Mark V that major changes were made to the design.


An initial order for 100 tanks was placed on 12 February 1916. This was split between Foster’s at Lincoln, who got 25 and Metropolitan in Birmingham, who got 75.

On 21 April another 50 Mark I Tanks were ordered. This time Fosters gained another five, Metropolitan the other 45. At about this time production was split into Male and Female, with 75 Male tanks (serial numbers 701 to 775) and 75 Female tanks (numbers 501-575).

The Mark I was also used as the basis for some special versions. The Mark I Tank Tender had the sponsons replaced with mild steel cargo boxes and could two three sledges carrying stories. It was used to transport troops or stores around the battlefield. It saw some use after April 1917.

The Mark I Wireless Tank was a female tank with the guns removed from the sponsons and wireless and office equipment installed. A pole mast was carried on the nose, with aerials rigged up the mast. The Wireless Tank was first used at the battle of Cambrai in November 1917.


The Mark I saw combat on the Somme in 1916 and at Arras in 1917.

The new tanks were originally attached to the Motor Machine Gun Service of the Machine Gun Corps, but the organisation’s name changed several times during 1916. It was the Heavy Section of the Machine Gun Corps from 1 May to 15 November 1916, then the Heavy Branch, Machine Gun Corps from 16 November 1916 to 26 July 1917, before becoming the Tank Corps on 27 July 1917.

Colonel Swinton, who had played a major roll in the development of the tank, was appointed as the first commander of the Tank Detachment, but as a home appointment only. In the field the tank force would come under the local commanders, a decision that played a part in the relative failure of the tanks in 1916 and much of 1917, as they were misused by commanders who had no idea of how they should be used, and what they couldn’t do. Colonel Swinton wanted to wait until enough tanks were ready to carry out a mass attack on well chosen ground, but instead the first few tanks were thrown into combat at Flers-Courcelette on the Somme on 15 September 1916 with limited success.

The new unit was given a secure tank training ground at Elvedon, Suffolk. Work on the new site began in late April, and by July it even had a spur off the nearby railway. Production of the tanks themselves went more slowly than expected. By 26 April it was clear that none would be ready by 1 June, but all 150 were expected by 1 August. By mid-June only 50 were expected by 1 August and the rest in September. Eventually they were completed by the end of October. As a result any hopes of a large scale attack to support the main fighting on the Somme disappeared.

The first two tanks had reached Elvedon by 20 June, and 20 had arrived by 10 July. The first sponsons arrived a week later. This allowed the start of gunnery training. Training revealed a number of flaws with the tanks that hadn’t shown up in shorter test runs – the structure wasn’t rigid enough and could flex so much that the gears disengaged, the track links weren’t strong enough, the belly plates were too weak and the drive wheel didn’t fully mesh with the links, causing a great deal of wear on the drive wheels.

The Somme

Early in 1916 General Haig had hoped to use the new tanks during the British offensive on the Somme. None were ready in time for the first day of the battle of the Somme on 1 July 1916, when the British Army suffered 60,000 casualties in a single day, its worst ever single day of losses. As the battle continued, Haig decided that he would use whatever tanks were available in a renewed major offensive in September. All of those involved in the tank were against the idea, believing that this would throw away the chance of winning a really significant victory with the new weapon, and would also give the Germans time to develop counters for the tank before they were available in significant numbers. In addition most of the tanks available would have to be taken from Elvedon, and would thus already be worn out.

The first tanks left Southampton heading for France on 20 August 1916. By 6 September 52 tanks had reached the assembly area, followed by another 25 later in the month (but too late to take part in the first tank attack). 48 tanks and 4 spares moved up to General Rawlinson’s Fourth Army by 10 September, ready to take part in an attack towards Morval, Les Boeufs, Gueudecourt and Flers on 15 September. This was a typically ambitious assault, with plans in place for a breakthrough towards Morval and Bapaume. The tanks were to work in groups of three, each attacking a number of German strong points. The initial plan was for the tanks to operate five minutes ahead of the infantry, operating in gaps in the artillery barrage.

Although the tanks weren’t being used as their advocates wanted, they still performed acceptably at the battle of Flers-Courcelette. Of the 48 tanks allocated to the attack 32 managed to reach the start points for their attack. Of these only nine managed to get keep ahead of the infantry, and they did live up to expectations, causing a great deal of shock amongst the Germans. Another nine managed to get going after overcoming various problems but they were too slow to catch up with the infantry and instead helped clear up un-captured German strong points. The other tanks all suffered from mechanical problems or got stuck attempting to cross the Somme battlefield. The most successful tank on the day was a Mark I Male, D17 ‘Dinnaken’ of D Company, which managed to advance 1.5 miles to Flers village, crushing a path through the German wire outside the village. The village was captured, but the tank had to be abandoned after suffering damage on the way back to Allied lines. Only two tanks were still combat ready on the following day, and they were both knocked out during an attack on Gueudecourt, but D17 had made the name of the tank. An RFC observer flying overhead had reported ‘Tank followed by cheering multitude marching through Flers’, and that message helped spread the fame of the tank around the world.

Haig was certainly won over by the performance of the tanks telling Swinton to make as many more as he could. Admiral Bacon, who was visiting the front at the time, was asked to inspect the Mark I, and judged it to be unsteerable, badly ventilated and too noisy and in great need of modifications, but also considered that 500 improved models could walk through the German lines.

In the aftermath of the battle an order was placed for 1,000 new tanks, but there was some confusion about what this actually meant – was it for more Mark I Tanks, 1,000 of an improved British type, or 1,000 of a new Anglo-French design? This order was then cancelled by the Army Council, which wanted to continue with the production of the remaining Mark Is and of the 50 Mark IIs and 50 Mark IIIs that had already been ordered while the performance of the tank was evaluated. Stern had already placed orders for 1,000 tanks with Metropolitan, and went directly to Lloyd George and on 14 October the cancellation was cancelled. These tanks would end up being improved Mark IV Tanks.


The Mark IV failed to reach France in time to take part in the major spring offensive of 1917 at Arras. Instead a mixed force of Mark II tanks (possibly built of boilerplate rather than armour plate) and a handful of remaining Mark Is was gathered. However despite all of these efforts they had little impact on the battle. None of the eight tanks that had been allocated to support the Canadian attack on Vimy Ridge reached the battlefield. The twelve tanks allocated to the Australians didn’t perform much better. The Australian attack was delayed twice, the second time because the tanks hadn’t arrived to carry out their part in the battle. When the attack was made those tanks that reached the battlefield performed acceptably, but the Australians had already formed their opinions and didn’t trust tanks for the next year. The main attack, east of Arras, was to be supported by 40 tanks, but once again most of them got bogged down. Some did get into the fight, most notably Lusitania, commanded by 2nd Lt Charles Weber, which helped with the capture of Feuchy Redoubt and Feuchy Chapel.

One minor benefit did come from the battle – the Germans captured a number of tanks almost intact. In tests their anti-tank ammo was able to penetrate the armour of the Mark I and Mark II, and they identified the fuel tanks, at the front of the tank, as a vulnerable target. However the new Mark IV Tank, which was about to enter combat, had thicker armour, which was more resistant to the ammo, and fuel tanks at the rear, so they were more resilient than the Germans had expected.


In December 1916 it was decided to send eight Mark I Tanks to Palestine. They reached the Suez Canal Zone in January 1917 and were committed to action during the Second Battle of Gaza in April 1917. They were split up into pairs and allocated to four different brigades, reducing any chance of success. Six tanks took part in the fighting on the first day of the battle, 17 April, and one was destroyed. Six tanks took part in the fighting on 19 April, when some of them performed well. However they were scattered across the battlefield, so could only have a local impact.


Production: 150?
Hull Length: 32.5ft
Hull Width: 13.75ft (male); 14.33ft (female)
Height: 8ft
Crew: 8
Weight: 28 tons (male), 27 tons (female)
Engine: 105hp Daimler-Foster gasoline engine
Max Speed: 3.7mph
Max Range:
Armament (Male): Two 6-pounder guns and three machine guns
Armament (Female): Five machine guns
Armour: 6-12mm


Books on the First World War | Subject Index: First World War

How to cite this article: Rickard, J. (4 July 2023), Mk I Tank (UK),

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