During WWI (1914-1918), 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. These vintage photographs show the incredible range of essential products made by women during the war. A large number of women were employed by the Lancashire and Yorkshire Railway during the first world war. Here, a group pose on a 4-4-2 High Flyer class locomotive, No 1406, at Low Moor engine shed near Bradford, 23 March 1917. Photograph: SSPL via Getty Images. A woman at work in an armaments factory, during the first world war. Photograph: Hulton Archive/Getty Images. A woman driving a wagon and horses in north London during the first world war. The picture was taken on 16 August 1916. Photograph: Topical Press Agency/Getty. Women railway employees during the first world war. Photograph: Branger/Roger Viollet/Getty Images. A woman tram driver, pictured in 1916, during the first world war. Photograph: Royal Photographic Society/SSPL via Getty Images. Five women ambulance drivers of the First Aid Nursing Yeomanry during the first world war, pictured at Calais in January 1917. Photograph: IWM via Getty Images. Lady Florence Norman, a suffragette, on her motor-scooter in 1916, travelling to work at offices in London where she was a supervisor. The scooter was a birthday present from her husband, the journalist and Liberal politician Sir Henry Norman. Photograph: FPG/Getty Images. A woman 'land girl' driving a tractor ploughing a field in March 1918. Photograph: Topical Press Agency/Getty. A woman mechanic repairing a car at a Women's Volunteer Reserve garage. Photograph: Hulton Archive/Getty Images. Two women porters at Marylebone station in London in 1914, loading wicker baskets onto a trolley. Photograph: Topical Press Agency/Getty Images. A woman assembly line worker at a munitions factory in 1917, during the first world war. Photograph: Hulton-Deutsch Collection/Corbis. Members of the women's police service during the first world war. Photograph: Hulton Archive/Getty. Women workers feed a charcoal kiln used for purifying sugar at a refinery in Scotland during the first world war. Photograph: IWM via Getty Images. A women bus conductor has a warming drink of hot milk beside her south London bus, in February 1916. Photograph: Topical Press Agency/Getty. Women window cleaners working in Nottingham during the first world war, in 1917. Photograph: Heritage Image Partnership Ltd/Alamy. Workhouse women watch female workers demonstrate rescuing skills, as part of firefighting training, in April 1917. Photograph: American Press Association/Corbis. Women workers assembling artillery shells at a Vickers munitions factory, during the first world war. Photograph: Hulton-Deutsch Collection/CORB. Female construction workers push wheelbarrows loaded with earth, in Coventry, during the first world war. Photograph: Central Press/Getty Images. Female workers at an engineering factory, in 1917, during the first world war. Photograph: Hulton-Deutsch Collection/Corbis. (via The Guardian)