The terms of the union between Great Britain and Ireland were embodied in eight articles which came into force on 1 January 1801.
The kingdom was now to be known as The United Kingdom and Great Britain and Ireland (UK), which it remained until 1920. On 2 August 1800 the Irish Parliament met for the last time.
For the first time since Cromwell, England - including Wales - Ireland and Scotland were represented in one Parliament based at Westminster, which now added 32 Irish peers and 100 MPs to its ranks.
All pending appeals were to be decided in the UK House of Lords.
Parliamentary union was unpopular with many in Ireland. Almost ten years after the birth of the UK there was a Great Repeal meeting in Dublin, a movement boosted when Daniel O'Connell was elected the MP for Clare in 1828. He could not, though, take his seat until 1829, when Catholics were again admitted to Parliament as MPs under the Catholic Emancipation Act.
In April 1834 O'Connell brought the issue of repeal before the Commons, but was defeated by 523 votes to 38. He kept up the pressure by forming a Repeal Association in 1840, and later he declared 1843 the repeal year.
Government and Parliamentary opinion, however, remained committed to the union.
On 9 May 1843 Sir Robert Peel, the Prime Minister, told the House of Commons that he would do anything required to defend the union, even if it meant seeking fresh powers from Parliament.