French officer having tea with English military personnel during World War I. Between 1914 and 1918 the British and French were allies against the Central Powers after Belgium and a small part of northern France had been invaded by the German army. There was strong co-operation between the British and French forces. The battles took place on several different fronts, but most particularly to Anglo-French relations in the trenches in France and Belgium against the Germans. Unable to advance against the combined primary alliance powers of the British, French, and later American forces as well as the blockade preventing shipping reaching German controlled North Sea seaports, the Germans eventually surrendered after four years of heavy fighting. Bain News Service, circa 1914/18.