Members of the British National Front (NF) clash with anti-NF demonstrators in Lewisham, London, resulting in 214 arrests and at least 111 injuries.

The Battle of Lewisham took place on 13 August 1977, when 500 members of the far-right National Front (NF) attempted to march from New Cross to Lewisham in southeast London and various counter-demonstrations by approximately 4,000 people led to violent clashes between the two groups and between the anti-NF demonstrators and police. 5,000 police officers were present and 56 officers were injured, 11 of whom were hospitalised. 214 people were arrested. Later disturbances in Lewisham town centre saw the first use of police riot shields on the UK mainland.

The National Front (NF) is a far-right, fascist political party in the United Kingdom. It is currently led by Tony Martin. As a minor party, it has never had its representatives elected to the British or European Parliaments, although it gained a small number of local councillors through defections and it has had a few of its representatives elected to community councils. Founded in 1967, it reached the height of its electoral support during the mid-1970s, when it was briefly England's fourth-largest party in terms of vote share.

The NF was founded by A. K. Chesterton, formerly of the British Union of Fascists, as a merger between his League of Empire Loyalists and the British National Party. It was soon joined by the Greater Britain Movement, whose leader John Tyndall became the Front's chairman in 1972. Under Tyndall's leadership it capitalised on growing concern about South Asian migration to Britain, rapidly increasing its membership and vote share in the urban areas of east London and northern England. Its public profile was raised through street marches and rallies, which often resulted in violent clashes with anti-fascist protesters, most notably the 1974 Red Lion Square disorders and the 1977 Battle of Lewisham. In 1982, Tyndall left the National Front to form a new British National Party (BNP). Many NF members defected to Tyndall's BNP, contributing to a substantial decline in the Front's electoral support. During the 1980s, the NF split in two; the Flag NF retained the older ideology, while the Official NF adopted a Third Positionist stance before disbanding in 1990. In 1995, the Flag NF's leadership transformed the party into the National Democrats, although a small splinter group retained the NF name.

Ideologically positioned on the extreme right or far right of British politics, the NF has been characterised as fascist or neo-fascist by political scientists. Different factions have dominated the party at different times, each with its own ideological bent, including neo-Nazis, Strasserites and racial populists. The party espouses the ethnic nationalist view that only white people should be citizens of the United Kingdom. The NF calls for an end to non-white migration into the UK and for settled non-white Britons to be stripped of their citizenship and deported. A white supremacist party, it promotes biological racism and the white genocide conspiracy theory, calling for global racial separatism and condemning interracial relationships and miscegenation. It espouses anti-semitic conspiracy theories, endorsing Holocaust denial and claiming that Jews dominate the world through both communism and finance capitalism. It promotes economic protectionism, hard Euroscepticism and a transformation away from liberal democracy, while its social policies oppose feminism, LGBT rights and societal permissiveness.

After the BNP, the NF has been the most successful far-right group in British politics since the Second World War. During its history, it has established sub-groups such as a trade unionist association, a youth group and the Rock Against Communism musical organisation. Only whites are permitted membership of the party, and in its heyday most of its support came from white British working class and lower middle class communities in northern England and east London. The NF has generated vocal opposition from left-wing and anti-fascist groups throughout its history, and NF members are prohibited from various professions.