After the 1926 Imperial Conference , attended by Cosgrave as President of the Executive Council of the Irish Free State , the King 's title was changed under the Royal and Parliamentary Titles Act 1927 . The altered title , as proclaimed in London , replaced the words " ... of the United Kingdom of Great Britain and Ireland and ... " with " ... of Great Britain , Ireland and ... " . This change did not stop the Irish government using the description " His Majesty 's Government in the Irish Free State " in agreements between the monarch 's governments in the United Kingdom and in the Irish Free State , as in : The description was also in regular official use between 1929 and 1934 in Notes published by HMSO , " in Regard to Commercial Relations " formally exchanged " Between His Majesty 's Government in the Irish Free State " and foreign governments including the governments of : and in other such Notes , including : In a debate in the Dáil in December 1932 , when de Valera was President , on a government motion to approve a trade agreement negotiated at the Ottawa Conference in August between the Irish Free State and the Dominion of Canada , it was remarked that the Vice-President ( Ernest Blythe ) had signed the agreement " on behalf of His Majesty 's Government in the Irish Free State . " But the description went out of use at least by 1937 , when the Constitution of Ireland came into effect as a result of de Valera 's process of constitutional autochthony . Any remaining vestige of the monarch 's part in the constitution , or doubt about the person or office of the head of state , was removed when the state was finally declared to be a republic , as from 18 April 1949 , under the Republic of Ireland Act 1948
1926 Imperial Conference
1926 Imperial Conference
Executive Council of the Irish Free State