December 1915: A crowd of young men queuing up at the Army Recruiting Office at Southwark Hall, south London, during Lord Derby's recruitment campaign. (Photo by Topical Press Agency/Getty Images)

December 1915:  A crowd of young men queuing up at the Army Recruiting Office at Southwark Hall, south London, during Lord Derby's recruitment campaign.  (Photo by Topical Press Agency/Getty Images)