British entry into World War I

The United Kingdom entered World War I on 4 August 1914, when King George V declared war after the expiry of an ultimatum to the German Empire. The official explanation focused on protecting Belgium as a neutral country; the main reason, however, was to prevent a French defeat that would have left Germany in control of Western Europe. The Liberal Party was in power with prime minister H. H. Asquith and foreign minister Edward Grey leading the way. The Liberal cabinet made the decision, although the party had been strongly anti-war until the last minute. The Conservative Party was pro-war. The Liberals knew that if they split on the war issue, they would lose control of the government to the Conservatives.