The Irish Question and the Empire after the war
The most serious problem after the World War I in British politics was resolving the Irish Question.
In 1916, at Easter, the Sinn Fein extremists, who demanded complete independence, had rebelled in Dublin (the "Easter Ring"). The rebellion had been crushed, and sixteen rebels executed. The Sinn Fein party thought that only through the use of force could the Irish obtain full independence; they formed an army, the Irish Republic Army (I.R.A), and used terrorists methods against the British police.
England was inclined to support a Protestant Ulster, recognizing, however, the independence of the rest of Ireland of Catholic religion; but the situation grew worse when the British government sent an undisciplined auxiliary police force against the Irish rebels. They used the same barbarous methods as Sinn Fein, which shocked British opinion and public sentiment and compelled the then Prime Minister Lloyd George to try for some agreement. After difficult negotiations, a settlement was last signed on December 6th, 1921. Britain recognized the status of Ireland (now Eire) as a "free State within the British Commonwealth of Nations". Ulster retained her existing status within the United Kingdom.
It soon became evident that for the Dominions (South Africa, Canada, Australia, New Zealand and Newfoundland), too, it was necessary to recognize the deep change that had come about in their relations with Britain. The Dominion had contributed to victory in World War I, but at the same time they had realized their collective power as self-governing communities. They had obtained representation at the Peace Conference of Versailles; they were separate members of the League of Nations; they were had their own Parliaments, their laws, a local government, a free press.
In effect they were independent, and the Imperial Conference held in London in 1926, recognized the Dominions as "autonomous Communities within British Empire, equal in status, in no way subordinate to one another in any aspect of their domestic or external affairs, though united by a common allegiance to the Crown, and freely associated as members of the British Commonwealth of Nations".
The legal recognition was contained in the Statute of Westminster, which was passed in 1931, and gave complete legislative power to the Dominions.
Ireland, too, took advantage of the Statute. Eamon de Valera, the new president of the Irish Republic, in 1933 abolished the aoth of allegiance to the British monarch as a head of the Commonwealth, and gave the Irish State the name of Eire. In the Second world War, Eire remained neutral, and did not allow the use of its ports to the Allied Forces. After the war, in 1949, De Valera announced Eire's secession from the Commonwealth.