The Great War, which some would argue was fueled by the industrial revolution and the mass production of weaponry helped to increase instability across Europe and in the beginning of 1914, the British Army had a reported strength of 710,000 men including reserves, of which around 80,000 were regular troops ready for war. By the end of World War I almost 1 in 4 of the total male population of the United Kingdom of Great Britain and Ireland had joined up, over five million men. Of these men, 2.67 million joined as Volunteers and 2.77 million as conscripts.
Between 1914 and 1918, a large numbers of women were recruited into jobs vacated by men who had gone to fight in the war. New jobs were also created as part of the war effort, for example in munitions factories. The high demand for weapons resulted in the munitions factories becoming the largest single employer of women during 1918. Though there was initial resistance to hiring women for what was seen as ‘men’s work’, the introduction of conscription in 1916 made the need for women workers urgent. Around this time, the government began coordinating the employment of women through campaigns and recruitment drives.
This led to women working in areas of work that were formerly reserved for men, for example as railway guards and ticket collectors, buses and tram conductors, postal workers, police, fire-fighters and as bank ‘tellers’ and clerks. Some women also worked heavy or precision machinery in engineering, led cart horses on farms, and worked in the civil service and factories. However, they received lower wages for doing the same work, and thus began some of the earliest demands for equal pay.
By 1917 munitions factories, which primarily employed women workers, produced 80% of the weapons and shells used by the British Army (Airth-Kindree, 1987). Known as ‘canaries’ because they had to handle TNT (the chemical compound trinitrotoluene that is used as an explosive agent in munitions) which caused their skin to turn yellow, these women risked their lives working with poisonous substances without adequate protective clothing or the required safety measures. Around 400 women died from overexposure to TNT during WWI.
During World War II, women were mobilised en masse to fill in for the men conscripted into war and 640,000 were in the armed forces; 55,000 serving with guns and providing essential air defence and 80,000 thousand in the Land Army. In the factories government figures show that women’s employment increased during the Second World War from about 5.1 million in 1939 (26%) to just over 7.25 million in 1943 (36% of all women of working age). Forty six percent of all women aged between 14 and 59, and 90% of all able-bodied single women between the ages of 18 and 40 were engaged in some form of work or National Service by September 1943.
 H M Government, 1943, p64