The British National Party (BNP) is a far-right, fascist political party in the United Kingdom. It is headquartered in Wigton, Cumbria, and its leader is Adam Walker. A minor party, it has no elected representatives at any level of UK government. Founded in 1982, the party reached its greatest level of success in the 2000s, when it had over fifty seats in local government, one seat on the London Assembly, and two Members of the European Parliament.

Taking its name from that of a defunct 1960s far-right party, the BNP was created by John Tyndall and other former members of the fascist National Front (NF). During the 1980s and 1990s, the BNP placed little emphasis on contesting elections, in which it did poorly. Instead, it focused on street marches and rallies, creating the Combat 18 paramilitary—its name a coded reference to Nazi German leader Adolf Hitler—to protect its events from anti-fascist protesters. A growing 'moderniser' faction was frustrated by Tyndall's leadership, and ousted him in 1999. The new leader Nick Griffin sought to broaden the BNP's electoral base by presenting a more moderate image, targeting concerns about rising immigration rates, and emphasising localised community campaigns. This resulted in increased electoral growth throughout the 2000s, to the extent that it became the most electorally successful far-right party in British history. Concerns regarding financial mismanagement resulted in Griffin being removed as leader in 2014. By this point the BNP's membership and vote share had declined dramatically, groups like Britain First and National Action had splintered off, and the English Defence League had supplanted it as the UK's foremost far-right group.

Ideologically positioned on the extreme-right or far-right of British politics, the BNP has been characterised as fascist or neo-fascist by political scientists. Under Tyndall's leadership, it was more specifically regarded as neo-Nazi. The party is ethnic nationalist, and it once espoused the view that only white people should be citizens of the United Kingdom. It calls for an end to non-white migration into the UK. Initially, it called for the compulsory expulsion of non-whites, although since 1999 has advocated voluntary removals with financial incentives. It promotes biological racism and the white genocide conspiracy theory, calling for global racial separatism and condemning interracial relationships. Under Tyndall, the BNP emphasised anti-semitism and Holocaust denial, promoting the conspiracy theory that Jews seek to dominate the world through both communism and international capitalism. Under Griffin, the party's focus switched from anti-semitism towards Islamophobia. It promotes economic protectionism, Euroscepticism, and a transformation away from liberal democracy, while its social policies oppose feminism, LGBT rights, and societal permissiveness.

Operating around a highly centralised structure that gave its chair near total control, the BNP built links with far-right parties across Europe and created various sub-groups, including a record label and trade union. The BNP attracted most support from within White British working-class communities in northern and eastern England, particularly among middle-aged and elderly men. A poll in the 2000s suggested that most Britons favoured a ban on the party. It faced much opposition from anti-fascists, religious organisations, the mainstream media, and most politicians, and BNP members were banned from various professions.