Britain declares war on Germany – On this day in history


04 August 2016
4-August-Pixabay-24475.jpg A First World War cemetery in Belgium
Britain goes to war with Germany in 1914

On 4 August 1914 Britain declares war on Germany. The war was effective from 11pm, following an ‘unsatisfactory reply’ from Germany to an ultimatum by the British Government under Prime Minister Herbert Asquith to keep Belgium neutral, as Germany began an invasion to reach France . Britain had guaranteed Belgium’s neutrality and independence since the 1839 Treaty of London and feared a German domination of Europe, threatening Britain's security and position in the world.

Britain's decision is seen as the start of the First World War, which was to last until 11 November 1918 and saw the deaths of millions of our ancestors in one of the deadliest conflicts in history. 

The Imperial War Museums’ branches are well worth visiting to learn more about your WW1 ancestors’ wartime experiences in the military and on the Home Front and you can search their collections at Other great websites for WW1 research include the Long, Long Trail at and the Commonwealth War Graves Commission (, along with the major commercial genealogy websites.

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Watch the first episode of the 1964 BBC documentary The Great War, which included interviews with veterans:

Trying to research your WW1 hero? Family Tree has fantastic tips every issue on what steps to take next, with pages of your Q&As each month to help you keep your research on track. Why not drop one of our military experts a line for some free advice? Find out how in our latest issue at