The First World War (1914–1918)

The First World War began in 1914. Britain entered the war after Germany invaded Belgium. Britain had guaranteed Belgian neutrality under a treaty, and the invasion of a neutral country provided the immediate cause for Britain's declaration of war against Germany in August 1914.

The war involved many of the world's major powers, forming two opposing alliances: the Allies (including Britain, France, and Russia) and the Central Powers (including Germany, Austria-Hungary, and the Ottoman Empire).

Much of the fighting on the Western Front took place in a network of trenches that stretched across Belgium and northern France. Conditions in the trenches were appalling. The war resulted in enormous casualties — millions of soldiers were killed or wounded. Poets such as Wilfred Owen and Siegfried Sassoon captured the horror of trench warfare in their writing.

The scale of the losses had a profound effect on British society. Virtually every family and community in the country was touched by the war.

During the war, women took on many roles previously done by men — working in factories, on the land, and in public services. This contribution strengthened the case for women's right to vote. In 1918, women over the age of 30 who met certain property qualifications were given the right to vote.

The war ended on 11 November 1918, when Germany signed an armistice. This date is now known as Armistice Day (Remembrance Day), and is commemorated each year with two minutes' silence at 11 am. Irish partition followed in 1922, partly as a consequence of the political upheaval the war produced.