On this day, Britain announces that all travel between Ireland and the United Kingdom is suspended, the result of the Irish government's refusal to expel Axis-power diplomats within its borders.
In 1922, an independent Irish republic was established after generations of conflict between Ireland and Britain. One of the conditions of that agreement was that Britain would retain control of three naval bases along the Irish coast in order to continue Ireland's defense. But as war loomed in the late 1930s, Irish Prime Minister Eamon de Valera negotiated an agreement that ended the British occupation of those naval bases; Ireland had declared a pre-emptive state of neutrality in any European war, and the presence of the Royal Navy on independent Irish soil violated that neutrality. De Valera did not want Ireland to become an object of attacks aimed at Britain.
De Valera was willing to bargain away Irish neutrality, though, in exchange for Northern Ireland's being returned to the Irish Republic. The British were not willing to pay that price but did agree to end conscription in Northern Ireland once De Valera denounced conscription--because it forced Irish men to fight in what De Valera believed was an English war--as an "act of aggression."
Irish neutrality was challenged in 1941, with German air raids against Dublin. It was challenged again in 1942, when the United States landed troops in Northern Ireland, under the understanding that it was under the control of its ally, Britain. De Valera protested. President Franklin D. Roosevelt was stunned at this intransigence and applied pressure to the de Valera government, attempting to change Ireland's neutrality stance. De Valera did not relent. Finally, when the Irish prime minister refused to expel from Ireland the diplomats of the Axis powers, Britain retaliated by suspending all travel between the Irish Republic and the United Kingdom. Ireland did not flinch and, when the war ended, developed good relations with all the powers involved.