The first proposal to send Cruiser tanks to the USSR was made in the spring of 1942. The British offered as a supplement to Matildas, Valentines, and Churchills: Cruiser Tank Mk.VI, or, since spring of 1941, Crusader. This successor to the Cruiser Tank Mk.III entered production towards the end of 1940. This was a completely new tank, and a much more successful one than its predecessor. At the same time, it retained some of their drawbacks, like weak armour and not exceptionally reliable Nuffield-Liberty engine.
GABTU made a request for information from appropriate organizations. In addition to official channels, foreign intelligence was activated, and obtained exact information on the production volume and the factories that make the tanks. At first, the tank was rejected due to its gasoline engine. Other tanks shipped to the USSR had diesel engines. In addition to this, information regarding the German evaluation of the Crusader in North Africa was obtained. The Germans considered the tank quick, but lightly armoured.
Meanwhile, the War Office has been thinking about a replacement for the Crusader since 1940, the same year it entered production. Requirements were given to three companies: Vauxhall, Nuffield, and Birmingham Railway Carriage & Wagon Company (BRC&W). The best result came from Nuffield, the A24. The Crusader served as the foundation for this 27 ton vehicle. The tank was adopted under the index Cruiser Tank Mk.VII or Cavalier, but the tank's fate was sealed from the very beginning. The fault of this was the same Nuffield-Liberty engine. This drawback opened up a path to the Crusader III, armed with a 6-pounder (57 mm) gun.
The problematic vehicle was not discarded, and it was decided to keep working on it. The result was two more tanks, both with the index A27, but with an extra letter. The A27L was the Centaur tank, produced by Leyland and equipped with the Nuffield-Liberty engine. The A27M was the Cromwell tank, produced by BRC&W and equipped with a Meteor, a reduced power version of the Merlin aircraft engine. The new engine was not only more reliable, but one third more powerful.
Soviet specialists encountered this new tank in 1942. On November 13th, a member of the trade representative commission in Great Britain, K. Olkovskiy, visited the Chobham proving grounds. Here he saw two experimental Cromwell I tanks without armament.
These tanks showed smooth driving on cross-country terrain. However, they were plagued by minor defects in the gearbox, and after 5 km off-road, the water in the radiator started boiling. Suspension springs broke several times. At Olkhovskiy's request, he was given the specifications for this vehicle. He did not believe the specified mass of 27 tons, and left with a general impression that the demonstration was staged to show that the vehicle was not ready. In his opinion, the British did not want to send this tank as a replacement for Matildas or Churchills. In reality, the tank was simply not ready. It took another year to perfect it.