Answer a question about this article:
London's defences were rapidly reorganised by General Pile, the Commander-in-Chief of Anti-Aircraft Command. The difference this made to the effectiveness of air defences is questionable. The British were still one-third below the establishment of heavy anti-aircraft artillery AAA (or ack-ack) in May 1941, with only 2,631 weapons available. Dowding had to rely on night fighters. From 1940 to 1941, the most successful night-fighter was the Boulton Paul Defiant; its four squadrons shot down more enemy aircraft than any other type. AA defences improved by better use of radar and searchlights. Over several months, the 20,000 shells spent per raider shot down in September 1940, was reduced to 4,087 in January 1941 and to 2,963 shells in February 1941.
The British were how far below the establishment of heavy anti-aircraft artillery?
one-third
The context mentions the equipment shortage in London and how it made a difference to air defences, which is questionable. It also states that Britain was one-third below the establishment of heavy anti-aircraft artillery AAA (or ack-ack)
Given this statement, we can conclude that "One third" would be an appropriate answer for the question: How far were British's below their standard number of weapons?.