British nationalism asserts that the British are a nation and promotes the cultural unity of Britons, in a definition of Britishness that may include people of English, Scottish, Welsh, and Irish descent (those living in both Northern Ireland and Great Britain and historically the whole of Ireland when it was within the United Kingdom). British nationalism is closely associated with British unionism, which seeks to uphold the political union that is the United Kingdom, or strengthen the links between the countries of the United Kingdom.
British nationalism's unifying identity descends from the ancient Britons who dwelt on the island of Great Britain. British nationalism grew to include people outside Great Britain, in Ireland, because of the 1542 Crown of Ireland Act, which declared that the crown of Ireland was to be held by the ruling monarch of England as well as Anglo-Irish calls for unity with Britain.
It is characterised as a "powerful but ambivalent force in British politics". In its moderate form, British nationalism has been a civic nationalism, emphasizing both cohesion and diversity of the people of the United Kingdom, its dependencies, and its former colonies. However, nativist nationalism has arisen based on fear of Britain being swamped by immigrants; this anti-immigrant nativist nationalism has manifested politically in the British National Party and other nativist nationalist movements. Politicians, such as former British prime minister David Cameron, have sought to promote British nationalism as a progressive cause.
Nowadays, as in the past, unionist movements exist in Scotland, Wales and Northern Ireland. These movements seek specifically to retain the ties between those areas and the rest of the UK, in opposition to civic nationalist movements. Such unionist movements include the Ulster Unionist Party, Democratic Unionist Party and the Scottish Unionist Party. In Scotland and Wales the Conservative, Labour, Liberal Democrat, and UKIP support the Union. British nationalists are generally supportive of unionism.
Being British is one of the most successful examples of inclusive civic nationalism in the world.The official party site.