Why were women important to the work at Bletchley Park?

Women were essential to the success of the Ultra intelligence project at Bletchley Park, comprising approximately three-fourths of the total workforce by late 1944.1

As the operation expanded from 200 staff members at the start of World War II to nearly 9,000 by the end of 1944, women were critical in maintaining the around-the-clock, three-shift schedule required to decode enemy messages encrypted by the Enigma and Tunny cipher machines. Their contributions were vital to the massive, high-priority effort that enabled code breakers to decipher secret communications, an achievement experts suggest may have shortened the war by as much as two years.1