1st Middlesex Regiment on parade, Woolwich, London, 1914-1918.

UNITED KINGDOM - DECEMBER 13: Photograph by Barnett showing the regiment on the parade ground. At the outset of the First World War the British Army was an entirely professional volunteer force. The British Expeditionary force sent to France in 1914 numbered 120,000, about half the Army�s entire strength. By the end of 1914, the casualties sustained made it obvious that a much larger number of troops was going to be required. The ensuing recruitment campaign produced some 2.6 million volunteers, sometimes whole streets or factories joining up together. By 1916, it had become necessary to introduce conscription to replace the losses. At the end of the war, British casualties stood at approximately 662,000 killed, 1.6 million wounded, and 140,000 missing, presumed dead. (Photo by SSPL/Getty Images)