The House of Lords votes on February 10, 1800 for the Acts of Union which sees Ireland lose its own parliament, direct rule is imposed on Ireland, and the United Kingdom of Great Britain and Ireland is created. The acts come into force on January 1, 1801, and the merged Parliament of the United Kingdom has its first meeting on January 22, 1801. Both acts remain in force, with amendments, in the United Kingdom of Great Britain and Northern Ireland, but have been repealed in the Republic of Ireland.

Before these Acts, Ireland had been in personal union with England since 1541, when the Parliament of Ireland had passed the Crown of Ireland Act 1542, proclaiming King Henry VIII of England to be King of Ireland. Since the 12th century, the King of England had been technical overlord of the Lordship of Ireland, a papal possession. Both the Kingdoms of Ireland and England later came into personal union with that of Scotland upon the Union of the Crowns in 1603.

In 1707, the Kingdom of England and the Kingdom of Scotland were united into a single kingdom: the Kingdom of Great Britain. The Irish Parliament at that time was subject to a number of restrictions that placed it subservient to the Parliament of England and, following the union of England and Scotland, the Parliament of Great Britain. Ireland, however, gained effective legislative independence from Great Britain through the Constitution of 1782.

By this time access to institutional power in Ireland was restricted to a small minority, the Anglo-Irish of the Protestant Ascendancy, and frustration at the lack of reform among the Catholic majority eventually led, along with other reasons, to the Irish Rebellion in 1798, involving a French invasion of Ireland and the seeking of complete independence from Great Britain. This rebellion was crushed with much bloodshed, and the subsequent drive for union between Great Britain and Ireland that passes in 1800 is motivated at least in part by the belief that the rebellion was caused as much by reactionary loyalist brutality as by the Society of United Irishmen.

Furthermore, Catholic emancipation is being discussed in Great Britain, and fears that a newly enfranchised Catholic majority will drastically change the character of the Irish government and parliament also contributes to a desire from London to merge the Parliaments.

Complementary acts have to be passed in the Parliament of Great Britain and in the Parliament of Ireland. The Parliament of Ireland had recently gained a large measure of legislative independence under the Constitution of 1782. Many members of the Irish Parliament jealously guard this autonomy and a motion for union is legally rejected in 1799.

Only Anglicans are permitted to become members of the Parliament of Ireland, though the great majority of the Irish population are Roman Catholic, with many Presbyterians in Ulster. In 1793 Roman Catholics regain the right to vote if they own or rent property worth £2 per acre. The Catholic hierarchy is strongly in favour of union, hoping for rapid emancipation and the right to sit as MPs, which is delayed after the passage of the acts until the passage of the Roman Catholic Relief Act 1829.

From the perspective of Great Britain, the union is desirable because of the uncertainty that followed the Irish Rebellion of 1798 and the French Revolution of 1789. If Ireland adopted Catholic Emancipation, willingly or not, a Roman Catholic Parliament could break away from Britain and ally with the French. Also the Irish and British Parliaments, when creating a regency during King George III‘s “madness”, gave the Prince Regent different powers. These considerations lead Great Britain to decide to attempt merger of the two kingdoms and their Parliaments.

The final passage of the Act in the Irish Parliament is achieved with substantial majorities, in part according to contemporary documents through bribery, namely the awarding of peerages and honours to critics to get their votes. Whereas the first attempt had been defeated in the Irish House of Commons by 109 votes against to 104 for, the second vote in 1800 produces a result of 158 to 115.

In the first Parliament of the United Kingdom of Great Britain and Ireland, the members of the House of Commons are not elected afresh. By royal proclamation authorised by the Act, all the members of the last House of Commons from Great Britain take seats in the new House, and from Ireland 100 members are chosen from the last Irish House of Commons: two members from each of the 32 counties and from the two largest boroughs, and one from each of the next 31 boroughs (chosen by lot) and from the University of Dublin. The other 84 Irish parliamentary boroughs are disfranchised, all being pocket boroughs, whose patrons receive £15,000 compensation for the loss of what is considered their property.

(Pictured: Coat of Arms of the United Kingdom from 1837 to 1952 used by Queen Victoria, King Edward VII, George V, Edward VIII and George VI)