"How was post-war British society different from the society that had entered the First World War in August 1914? It was indubitably more democratic. Previously under-represented groups such as women and, in particular, the working class became better organised and more powerful during the war. This, in turn, encouraged the growth of less deferential attitudes, as did the cross-class experiences of the trenches. There had been a disproportionately high percentage of casualties among the landed classes, and the strict class hierarchy of Edwardian Britain disappeared for good in the immediate post-war years.

Yet, though the working class became a more powerful political force, it shrank numerically. Growing numbers of the working population in inter-war Britain were employed in 'white collar' jobs. The First World War thus marked an important staging post on the road to 'modern' British society."
http://www.nationalarchives.gov.uk/pathways/firstworldwar/aftermath/brit_after_war.htm