<Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> The United Kingdom of Great Britain and Ireland was established as a sovereign state on 1 January 1801 by the Acts of Union 1800, which merged the kingdoms of Great Britain and Ireland . The growing desire for an Irish Republic led to the Irish War of Independence, which resulted in Ireland seceding from the Union and forming the Irish Free State in 1922 . Northern Ireland remained part of the United Kingdom, and the state was consequently renamed the "United Kingdom of Great Britain and Northern Ireland". </P> <P> The UK financed the European coalition that defeated France in 1815 in the Napoleonic Wars . The British Empire thereby became the foremost world power for the next century . The Crimean War with Russia and the Boer wars were relatively small operations in a largely peaceful century . Rapid industrialisation that began in the decades prior to the state's formation continued up until the mid-19th century . A devastating famine, exacerbated by government inaction in the mid-19th century, led to demographic collapse in much of Ireland, and increased calls for Irish land reform . </P>

When did ireland secede from the united kingdom