First World War recruitment poster for Voluntary Aid Detachments.
The Voluntary Aid Detachment (VAD) referred to a voluntary unit providing field nursing services, mainly in hospitals, in the United Kingdom and various other countries in the British Empire. The most important periods of operation for these units were during World War I and World War II.
The VAD system was founded in 1909 with the help of the Red Cross and Order of St. John. By the summer of 1914 there were over 2,500 Voluntary Aid Detachments in Britain. Of the 74,000 VAD members in 1914, two-thirds were women and girls.
At the outbreak of the First World War VAD members eagerly offered their service to the war effort. The British Red Cross was reluctant to allow civilian women a role in overseas hospitals: most volunteers were of the middle and upper classes and unaccustomed to hardship and traditional hospital discipline. Military authorities would not accept VADs at the front line.
Katharine Furse took two VADs to France in October 1914, restricting them to serve as canteen workers and cooks. Caught under fire in a sudden battle the VADs were pressed into emergency hospital service and acquitted themselves well. The growing shortage of trained nurses opened the door for VADs in overseas military hospitals. Furse was appointed Commander-in-Chief of the detachments and restrictions were removed. Female volunteers over the age of twenty-three and with more than three months' hospital experience were accepted for overseas service.
VADs were an uneasy addition to military hospitals' rank and order. They lacked the advanced skill and discipline of professional trained nurses and were often critical of the nursing profession. Relations improved as the war stretched on: VAD members increased their skill and efficiency and trained nurses were more accepting of the VADs' contributions. During four years of war 38,000 VADs worked in hospitals and served as ambulance drivers and cooks. VADs served near the Western Front and in Mesopotamia and Gallipoli. VAD hospitals were also opened in most large towns in Britain. Later, VADs were also sent to the Eastern Front. They provided an invaluable source of bedside aid in the war effort. Many were decorated for distinguished service.
E.M. Delafield, British author of the "Diary of a Provincial Lady" series and some 30 other novels; her experiences working at the Exeter Voluntary Aid Hospital provided her with material for one of her most popular novels, The War Workers, published in 1918 
Violet Jessop, British ocean liner stewardess trained as a VAD nurse after the outbreak of World War I. She had been a stewardess aboard the RMS Titanic when it sank in 1912 and was also aboard the hospital ship HMHS Britannic (the Titanic's sister ship) as a Red Cross nurse when it sank in 1916.
The novel Not So Quiet . . . by Helen Zenna Smith (a pseudonym for Evadne Price) recounts the experiences of VAD ambulance drivers who evacuated the casualties of World War I.
The character of Georgina Worsley becomes a VAD in the fourth series of Upstairs, Downstairs, a fictional narrative based on the diaries of Lady Cynthia Asquith who was a VAD in the First World War.
In the eighth chronological book of the Anne of Green Gables series, Rilla of Ingleside by L. M. Montgomery character Faith Meredith is a VAD. This is one of the few contemporary books to show the Canadian point-of-view during WWI.
The character Celia Coplestone in T.S. Eliot's play The Cocktail Party (1949) becomes a VAD nurse after her failed affair with Edward Chamberlayne.
The character of Lady Sybil Crawley becomes a VAD in the second series of Downton Abbey, the TV series that follows the lives of the aristocratic Crawley family and their servants.
The novels A Girl Called Thursday and the sequel A Promise to Keep by Lilian Harry, also the character Val from the Burracombe Series of novels by the same author.