Limitations of the existing 2-pounders were apparent even as the gun entered service and an effort was made to replace it with a much more capable weapon starting as early as 1938. The Woolwich Arsenal was entrusted with the development of a new gun with a calibre of 57 mm. Guns of this calibre had been employed by the Royal Navy from the late 19th century and manufacturing equipment was available. The gun design was complete by 1940 but the carriage design took until 1941. The production was further delayed by the defeat in the Battle of France. The loss of equipment – most of the heavy equipment of the British Expeditionary Force (BEF) was left behind in France during Operation Dynamo – and the prospect of a German invasion made re-equipping the army with anti-tank weapons an urgent task, so a decision was made to carry on the production of the 2-pounder, avoiding the period of adaptation to production and also of re-training and acclimatisation with the new weapon. It was estimated that 100 6-pounders would displace the production of 600 2-pounders.