Britain and the First World War 1914–1918

The First World War transformed Britain more profoundly than any event since the Industrial Revolution. It expanded the state, empowered the labour movement, enfranchised women, destroyed the Liberal Party, and created the conditions for the welfare state. This lesson examines the political, social, and economic impact of the war on British society — analysing the historiographical debates about whether the war accelerated existing trends or produced genuinely revolutionary change.

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Britain's Entry into the War

Britain declared war on Germany on 4 August 1914, ostensibly in defence of Belgian neutrality under the 1839 Treaty of London. The Cabinet was deeply divided: two ministers resigned (John Burns and Lord Morley). Public opinion was initially uncertain but rallied rapidly.

Factor	Detail
Belgian neutrality	The German violation of Belgian neutrality provided the immediate moral justification
Balance of power	Britain's strategic interest in preventing any single power from dominating the European continent
Entente obligations	Informal commitments to France, including secret military conversations since 1906
Naval rivalry	The Anglo-German naval arms race had poisoned relations since 1898

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