What role did the British Expeditionary Force play in World War I?

The B.E.F were the British unit of soldiers sent to the Western Front. Their aim and fire power was so good, many Germans reported believing they were being attacked by machine gun fire!

That was at the first British battle in WW1 in 1914 at Mons, but previous to that Great Britain had signed the Treaty of London 1839 with Belgium which respected and guaranteed the neutrality of Belgium in war but the German Empire invaded Belgium and violated that treaty and because of this August the 4th 1914 Great Britain declared war.

However the BEF played a massive part in WW1 Western front, Macedonia, Gallipoli, Italy, all over the Middle East, Africa, and not to mention the Royal navy in their campaigns as well.

But to give you an insight on the BEF contribution throughout and the many battles they fought in Britain alone not including Empire troops from 1914-1919 sent over 5 million men to fight in all the campaigns, peaking at 1.7 million in France in 1917.