On February 4, 1915, Admiral Hugo von Pohl of the German High Seas Fleet warned that ‘every enemy merchant vessel’ in British waters would be targeted and that ‘it may not always be possible to prevent attacks on enemy ships from harming neutral ships’.

The Military Service Act made all single men and childless widowers between the ages of 18 and 41 liable to be called up. It received royal assent on 27 January but was met with a protest demonstration of approximately 200,000 people in London’s Trafalgar Square, while by July almost 30% of those called up to fight had failed to appear.

The assassination of Archduke Franz Ferdinand by Gavrilo Princip in 1914 had a direct effect on the outbreak of war, while the Treaty of Versailles was signed on exactly the same date five years later in 1919.