most likely because they were able to predict the future and knew hitler would kil them all anyway
They had alliances with countries that were involved.
Japan had early alliances with Germany. They were promised the Pacific Island holdings of the US if the Axis powers won the war.
Germany's aggressive actions in the early 20th century, particularly its invasion of Belgium in August 1914, prompted Britain to enter World War I. Britain had a longstanding commitment to protect Belgian neutrality, established by the Treaty of London in 1839. When Germany violated this neutrality as part of its war strategy, Britain declared war on Germany on August 4, 1914, in defense of Belgium and to uphold its commitments. Additionally, the broader context of rising tensions and alliances in Europe played a significant role in Britain's decision to join the conflict.
Germany invaded Belgium that was neutral
No
Britain joined the Triple Entente in 1907, solidifying its alliances with France and Russia. This agreement was partly a response to the growing threat posed by the Central Powers, particularly Germany. The Triple Entente aimed to counterbalance the military strength of the Triple Alliance, which included Germany, Austria-Hungary, and Italy.
Britain declared war on Germany on August 4, 1914 after Germany invaded Belgium.
Britain and Germany were rivals in World War I due to a combination of militarism, imperial ambitions, and alliances. Germany's rapid industrialization and naval expansion threatened Britain's longstanding naval supremacy and colonial interests. The formation of military alliances, such as the Triple Entente between Britain, France, and Russia, contrasted with Germany's alliance with Austria-Hungary and Italy, escalating tensions. These rivalries culminated in the outbreak of war in 1914 after the assassination of Archduke Franz Ferdinand, which triggered a complex web of alliances and conflicts.
Britain declared war on Germany on 3rd September 1939, two days after Germany invaded Poland.
There were no other alliances apart from the Triple Entente - Britain, France & Russia and the Triple Alliance - Germany, Austria-Hungary & Italy. They are were the only alliances involved not true Britain had an Alliance with Belgium and Russia had an Alliance with Serbia
Britain, Russia and France. Germany, Italy and Austria-Hungary.
In order to protect itself against other country's with their help. It works both ways in an alliance.