The Irish house of commons in the eighteenth century was composed of 300 members: two were elected by each of the 32 counties; two by 117 boroughs; and two by Trinity College, Dublin. Only protestants were returned, for by an English act of 1691 all members of the Irish house of commons were required to take oaths of allegiance and supremacy. Catholics could still exercise the franchise until 1727, but an act of that year deprived them of the right to vote. The dissenters were equally excluded: a clause in an act of 1704 requiring all office-holders to receive communion according to the usage of the established church excluded them from the corporations and indirectly from the house of commons. Even the minority that remained was very inadequately represented.

In the counties the leading landlords were able to influence the return of members, and many of the Irish boroughs were quite as rotten as any in England prior to 1832. Bannow in co. Wexford, for example, was a mountain of sea-sand without a single inhabited house; at Clonmines in the same county there was one solitary house; at Harristown in co. Kildare there was none. A traveller in Ireland in 1755 found Naas ‘a shabby looking place’; Castle Dermot ‘a very poor town’; Callen ‘a poor dirty town, interspersed with the numerous ruins of old castles and religious houses’; Rathcormac ‘a poor borough’; and Kilmallock ‘a spacious street, composed of houses, which, though magnificent, were windowless and roofless’. The conclusion he came to was: ‘Happy would it be for Ireland, if her corporate towns were divested of the privilege of returning representatives to the great council of the nation; for it becomes the selfish policy of the lord of the soil to impoverish the voters into compliance’.