Both the Allies and the Central Powers tried various
means to overcome the stalemate of trench warfare that characterised
the fighting on the Western Front from the autumn of 1914 onwards.
In April 1915, for example, German forces at the 2nd Battle of Ypres
released 168 tons of poisonous chlorine gas against French and Canadian
troops. But this dangerous new weapon did not have the intended
decisive impact. Within days, Kitchener had secured Cabinet agreement
for Britain to respond in kind.
In 1916, while German forces unsuccessfully laid
siege to the French fortress of Verdun
(February-August), the British launched a major set-piece offensive
of their own. The Battle
of the Somme began on 1 July 1916 and lasted until 17 November.
Nearly 20,000 British officers and men were killed on the first
day of fighting - more than on any other day during the war or on
any day in any other conflict. Yet, during the five-month offensive,
Allied troops made only small territorial gains.
The majority of the British forces on the Western
Front came from Britain itself, but there were also large numbers
of Indian combat troops as well as soldiers from the Dominions (Canada,
Australia, New Zealand and South Africa). Black soldiers from the
Caribbean and parts of Africa worked as labourers, often under fire.