from the link,
As the main historian of women's work, Gail Braybon, claims, for many women the war was "a genuinely liberating experience" (link) that made them feel useful as citizens but that also gave them the freedom and the wages only men had enjoyed so far. Approximately 1,600,000 women joined the workforce between 1914 and 1918 in Government departments, public transport, the post office, as clerks in business, as land workers and in factories, especially in the dangerous munitions factories, which were employing 950,000 women by Armistice Day (as compared to 700,000 in Germany).