the Section Sanitaire Anglaise, which was made up of British volunteers, typically ambulance drivers, attached to the French and or Belgian Armies.
This particular British volunteer unit SSA 14, photographed in 1916, was based in the Northern French costal town of Dunkerque just 6 miles from the Belgian border, and consisted mainly of Quakers from the Friends Ambulance Unit ( FAU ) who were usually also Conscientious Objectors.
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