The Cruiser Tank Mk III (A13) was the first in a long series of British cruiser tanks to feature Christie suspension, and this combined with a more powerful engine than the earlier Mk I or Mk II greatly improved the performance of the tank. Early in 1938 a production order was placed for 65 A13 Cruiser Tank Mk IIIs. The first production tank appeared early in 1939 and production was completed by the summer of the same year. At the time as the first batch of Cruiser Tank Mk III A13s was close to complete, during 1938 the General Staff decided to continue production of the basic design, but with the armour increased to the new 30mm standard. On the fuselage this was achieved by bolting extra plates of armour directly onto the existing armour. The turrets were given spaced armour, with the extra plate carried in a V-shape on the sides, giving the turret of the Mk IV a distinctive diamond profile from the front. The maximum thickness of armour on the nose, glacis plate and turret front was increased to 30mm, thus increasing the weight to 33,040 lb (15,018kg). The cruiser tank Mk IV was a logical development of the earlier Mk III, and a number of the earlier machines were subsequently uparmoured to Mk IV standard.Redesigned Mark III tanks were named Mark IV and retained coaxial Vickers machine gun. And the new tanks, equipped with a different gun mantlet and BESA machine gun — were named Mark IVA.
The A13 Mk II Cruiser tank Mk IV made up part of the equipment of the 1st Armoured Division when it was rushed to France in May 1940. One regiment was sent to Calais, where it lost all of its tanks very quickly. The rest of the division landed at Cherbourg and advanced to join the new French line on the Somme. After a limited attack on the German lines the division was forced to take part in the retreat into western France, eventually returning to Cherbourg. As at Dunkirk the tank crews were rescued but the tanks left behind.
After the fighting the Cruiser Tank Mk IV came in for some criticism. Its Liberty engine was unreliable and had an average lifespan of only 100 hours. The tracks were too thin, too smooth and came off too easily. The commander’s cupola was also flawed, and on a number of occasions was swept away complete with the commander’s head. Even the high speed wasn’t much of an asset, and was said to have been of most use during the retreat.
Some of these faults were due to the inexperience of the crews, many of whom had been issued with their tanks in the days before the fighting began. In the Western Desert the engine at least was more reliable, and the A13 took part in some cross-country journeys of several hundred miles without any problems.
The applique armour did not apply to the gun mantlet, which remained 14 mm thick. This problem was solved with additional spaced armour that covered the gun mantlet. These tanks were the most numerous among those equipped with a Vickers Mk.VI machinegun.
A13 Mk II (Cruiser tank Mk III uparmoured to Mk IV standard) cruiser tank fitted with additional turret applique armor and box-type additional armor of gun mauntlet.
After the 1940 campaign, several tanks (up to six) made it to the proving grounds at Kummersdorf. The other tanks were spread out between training and active units. In February of 1941, 9 tanks were transferred to Beutepanzer-Kompanie (e) within Pz.Abt. (Flamm) 100. Tanks that were used by training units were not changed significantly. Some tanks even retained British camouflage.
Tanks from Pz.Abt. (Flamm) 100 were also mostly unchanged from the fall of 1940 to spring of 1941. Notek night lights were installed, the tanks were painted in a German grey, and unit markings were added. As for tanks that were sent to the front lines, the modernization was systematic: all tanks were altered in the same way.
First, tanks from Pz.Abt. (Flamm) 100 received new tracks, borrowed from the Pz.Kpfw.II Ausf. D1. The cause of this replacement was that the new tracks were longer lasting. A bigger change compared to the original design was the addition of wooden shelves along the sides for fuel canisters, located behind the skirt armour. Holders for canisters were also added on the fenders. Front and rear mudguards were replaced with simplified ones. At the same time, the side elements of the fenders were removed.
In addition to standard lights, Notek night driving lights were added to the front and rear. The muffler was partially covered by a screen, and a mount for an unditching log was added. At least one tank from Pz.Abt. (Flamm) 100 (turret number 265) received a movable tow hook for a Renault UE trailer. Almost all Kreuzer Panzerkampfwagen Mk IV 744 (e) in Pz.Abt. (Flamm) 100 were of the later type.
Converted tanks were used in the first days of the Great Patriotic War. Tanks from Pz.Abt. (Flamm) 100 of the 18th Tank Division were included in the 2nd Tank Group of Army Group Center. The battalion participated in the assault on Brest Fortress and later fought in Belarus. However, the combat career of the Kreuzer Panzerkampfwagen Mk IV 744 (e) was not long. By July 11th, 1941, three weeks after combat began, the battalion no longer had a single tank of this type. Most were lost due to breakdowns.