Allied troops, under German bombardment, file through the town of Dunkirk on their way to the beaches to be rescued and taken to England.

Dunkirk under attack

Damaged Cruiser,abandoned in Calais,May 1940 
 
The Tank, Cruiser, Mk I (A9) was a British cruiser tank of the interwar period. It was the first cruiser tank: a fast tank designed to bypass the main enemy lines and engage the enemy's lines of communication, along with enemy tanks. The Cruiser Mk II was a heavier armoured adaptation of the Mark I developed at much the same time.

In 1936 the British War Office designated two different kinds of tanks for future development: heavily armoured infantry tanks to be used in close co-operation with infantry during attacks, and fast mobile cruiser tanks designed to make forays deep into enemy territory.

In 1934 Sir John Carden of Vickers-Armstrong had produced a new medium tank, the A9, which was subsequently designated the Cruiser Tank Mark I. It incorporated the best features of the earlier Mk III Light Tank, and was powered by a commercial petrol engine. However, this was still in the time of the Great depression and the tank had a number of cost-cutting measures applied. It was the first British tank to have a centrally-located turret, but was poorly armoured, with a maximum of 14 mm thickness, many armour faces were vertical, and there were numerous shot traps.

The driver's compartment and the fighting compartments were not separated. As well as the turret armament, which consisted of a QF 2-pounder (40 mm) gun and a coaxial Vickers machine gun, there were two small turrets either side of the driver's compartment, each sporting one more machine-gun. Both these smaller turrets were permanently manned, which gave the tank a total crew of 6 (Commander, gunner, loader, driver and two machine-gunners).

The tank entered testing in 1936 and 125 were ordered in the summer of 1937 as an interim design pending the delivery of a Cruiser tank based on the Christie suspension. 75 were built by Harland and Wolff, and the other 50 were built by Vickers. Originally a Rolls-Royce car engine was used, but this proved underpowered and was replaced by an AEC bus engine.

The later Valentine Infantry tank essentially used the same lower hull and suspension, though with considerably more armour.

The A9 weighed 12 tons, was 5.8 metres long, 2.65 metres high, 2.5 metres wide, and had a top speed of 25 mph on road and 15 mph off. Its maximum road range was 150 miles. The ammunition load was 100 2-pounder rounds and a total of 3,000 rounds for the three Vickers machine guns.

The Cruiser was an effective tank in the French, Greek and early North African campaigns. The 2 pdr gun was lethal against the early Italian tanks encountered during the North African campaign and could hold its own against Rommel's early Panzer IIs and IIIs. The A9's 2-pounder gun could also breach the 20 – 30 mm of protective steel on later opponents such as the Panzer III varient D and the Panzer IV D. It was effective until the Germans introduced the more thickly armoured Panzer IV E varient to the desert in Spring 1941. However, the minimal armour made the A9 an easy kill for most Axis anti-tank weapons. Also problematic was the lack of High Explosive shells for the 2 pdr gun and even worse the lack of AP for the 95 mm gun on the Close Support version. Another issue was that the areas around the front machine gun turrets created a frontal surface that was more vulnerable to enemy fire than it would have been had it been a flat plate, let alone a sloped glacis.

The mechanical unreliability of the Cruiser was also a disadvantage. In particular, tracks were easily slewed causing difficulties.

Specifications 
Weight 12 tons 
Length 19 ft (5.8 m) 
Width 8 ft 4 in (2.5 m) 
Height 8 ft 8 in (2.65 m) 
Crew 6 (Commander, gunner, loader, driver, 2x MG gunners) 
~~brummbar~~

A9 Cruiser MkI

These were among the oddly assorted craft that crossed the Channel from England to evacuate Allied troops from Dunkirk.