In 1916, a Butterick guide for dressmakers assumed a preference for open-crotch knickers as it produced only brief instructions for closed ones. This indicates that that there were still many women who did not wish to wear knickers with a closed crotch. However, this may principally have been a preference among women who made their own drawers because of an aversion to the closed-crotch alternatives. With the First World War(1914-18) came a period of profound social upheaval. As the nation's menfolk were called away to fight in the trenches, women were obliged to take on their temporarily-vacated civilian jobs or to work on the land or in the munitions factories. Naturally women in these positions quickly forsook their impractical skirts and dresses in favour of trousers and this in turn promoted the wearing of closed drawers for reasons of comfort and hygiene.
Some black underwear was worn during this time, probably under black dresses. However, it was not wholly acceptable to most women for general wear as it was seen as erotic. The Vogue magazine advertised some cami-knickers in 1916 that were red with black frills around the legs and the top. The same magazine also advertised black cami-knickers in 1924. mi-knickers consisted of a camisole and knickers made in one piece, The camisole was an item of underwear which covered the upper body to the waist. Cami-knickers, which consisted of a chemise with a button underneath, were introduced around 1917. They were also called step-ins and cami-combinations, but the Americans called them 'envelope chemises. A chemise was an undergarment similar to a modern knee-length petticoat. The old-style combinations stared to disappear and newer combinations became shorter in the leg and much fancier than their predecessors.
The mid-1920s saw the shortest skirts ever known up to that time, ending just above the knee, which dictated the wearing of closed-crotch knickers that were shorter than those worn previously. This was a decade of great social pleasure with many parties, dances and fun times available made possible by an improvement in the country's economy. Young people enjoyed learning the new dances from the USA such as The Charleston and The Black Bottom, both of which involved moving fast and jumping around. The short dresses worn by young women would have flipped around, often showing their thighs and underwear. In her autobiography, the Duchess of Argyle noted that when she was a young woman in the 1920s her mother made a comment having heard that her daughter planned to attend a dance one evening: "If you are going to be flung around the ballroom by Billy, I insist that nanny buys you a pair of bloomers with clastic round the legs
French knickers became fashionable in the later part of the decade with wide, square legs ending at the knee and often featuring ornate embroidery. However, Directoire knickers were still considered to be practical. Almost all fashionable knickers now had a closed crotch, though many older women continued to wear open-crotch drawers Cami-knickers grew in popularity in the 1920s, particularly those made from Crepe de Chine, as silk fabrics were now much more available than during the years of the war. They fitted very nicely underneath the skimpy dresses of the time and were very light to wear. Lingerie at this time was narrow and not bulky. During this era, many different styles of knickers were being worn. Cami-knickers could have been loose or tight around