Canadians at nominal scrap value. The tank itself was long and tall. At its widest across the sponsons it was . There had been an even longer 44-foot (13.4 m) version planned but never made (the Mark VIII*). The tank was outdated by the 1930s due to its slow speed (under 6 mph/10 km/h) and thin armour (16–6 mm), but it did have one of the longest independent trench crossing capabilities of any armoured fighting vehicle (AFV) ever made; later tanks used bridge laying tanks for crossing large deep trenches. Mark IX The Mark IX was a troop carrier and 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. Mark X 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. Combat history The first tanks were added, as a "Heavy Branch", to the Machine Gun Corps until a separate Tank Corps was formed on 28 July 1917 by Royal Warrant. A small number of Mark I tanks took part in the Battle of the Somme during the Battle of Flers-Courcelette in September 1916. They were used to cut through barbed wire to clear the way for infantry, and were even driven through houses to destroy machine gunner's emplacements. Although many broke down or became stuck, almost a third that attacked made it across no man's land, and their effect on the enemy was noted, leading to a request by the British C-in-C Douglas Haig for a thousand more. This came as a surprise: William Tritton had already started the development of a heavier tank: the Flying Elephant. Unfortunately for the Allies, it also gave the Germans time to develop a specifically designed anti-tank weapon for the infantry, an armour-piercing 7.92 mm K bullet. Eight Mk I tanks were used against Turkish forces in the Second Battle of Gaza in April 1917 during the Sinai and Palestine Campaign. With its three destroyed tanks replaced by Mk IVs, the tank company fought at the Third Battle of Gaza. British tanks