<P> Great Britain had been at war with France since 1792 . The Prime Minister since 1783, William Pitt the Younger, led a broad wartime coalition of Whig and Tory politicians . </P> <P> The principal opposition to Pitt was a relatively weak faction of Whigs, led by Charles James Fox . For four years after 1797 opposition attendance at Westminster had been sporadic as Fox pursued a strategy of secession from Parliament . Only a small group, led by George Tierney, had attended frequently to oppose the ministers . As Foord observes "only once did the minority reach seventy - five, and it was often less than ten". </P> <P> The Act of Union 1800 created the United Kingdom by merging the previous Kingdoms of Great Britain and Ireland . The first Parliament of the United Kingdom was composed of all the members of the last Parliament of Great Britain and some of the members of the final Parliament of Ireland . </P> <P> Pitt wished to grant Catholic emancipation (the right for Roman Catholics to sit in Parliament), to help reconcile the Irish Catholic majority with the Union . King George III was opposed to that policy, so Pitt was compelled to resign in March 1801 . </P>

Which british prime minister merged the british and irish parliaments in 1801