UKIP originated as the Anti-Federalist League, a single-issue Eurosceptic party established in London by Alan Sked in 1991. It was renamed UKIP in 1993, but its growth remained slow. It was largely eclipsed by the Eurosceptic Referendum Party until the latter's 1997 dissolution. In 1997, Sked was ousted by a faction led by Nigel Farage, who became the party's preeminent figure. In 2006, Farage officially became leader and, under his direction, the party adopted a wider policy platform and capitalised on concerns about rising immigration, in particular among the White British working class. This resulted in significant breakthroughs at the 2013 local elections, 2014 European elections, and 2015 general election. The pressure UKIP exerted on the government contributed to the 2016 referendum which led to the UK's commitment to withdraw from the European Union. Farage then stepped down as UKIP leader, and the party's vote share and membership heavily declined. Following repeat leadership crises, Gerard Batten took over. Under Batten, UKIP moved into far-right territory by emphasising an anti-Islam message. At this, many longstanding members—including Farage—left and joined the new Brexit Party. Since 2019, the party has faced large amounts of internal instability, with a number of changes to its leadership at a national level and a loss of presence in both the European Parliament and also the London Assembly.