In theory, Parliament in 1825 contained only practising members of the Church of England, the Church of Scotland or the established Church of Ireland. Protestant Dissenters were debarred by the Test and Corporation Acts, Roman Catholics by a patchwork of anti-Catholic legislation, from any active part in government. By 1825 the Test and Corporation Acts had been allowed to fall into abeyance. Roman Catholics, however, while no longer liable to penalties simply for professing their faith, were proscribed from serving as MPs, Crown ministers, judges or county sheriffs, and enjoyed no relief.

In England, Scotland and Wales this state of affairs was not particularly contentious. In Ireland it was a serious political grievance. An emancipation measure was widely expected to follow Pitt's Act of Union (1800), but the 1801 Catholic Relief Bill was abandoned in face of George III's opposition.

Throughout the first quarter of the nineteenth century, unsuccessful Bills and petitions for Roman Catholic relief punctuated the parliamentary calendar – Beilby Porteus debated one in May 1805. By 1821, the principle of Catholic Emancipation commanded a majority in the House of Commons, ‘despite the dominance of a Tory government committed to the union of church and state’. The Lords still stood firm.