Top Gear is a British television series about motor vehicles, primarily cars. It is a relaunched version of the original 1977 show of the same name, airing since 2002, and has become the most widely watched factual television programme in the world. Since the relaunch, the conventional motoring magazine programme has developed a quirky, humorous and sometimes controversial style over time, and has become a significant show in British popular culture. During its first 22 series, the programme received acclaim for its visual style and presentation as well as criticism for its content and often politically incorrect commentary made by its former presenters Jeremy Clarkson, Richard Hammond, and James May. Columnist A. A. Gill, close friend of Clarkson and fellow Sunday Times columnist, described the programme as "a triumph of the craft of programme making, of the minute, obsessive, musical masonry of editing, the French polishing of colourwashing and grading".
The show's relaunched format was originally hosted by Clarkson, Hammond and Jason Dawe, with Andy Wilman as the show's executive producer, and introduced an anonymous test driver known as "The Stig"; although part of the line-up, "The Stig" has been played by numerous racing drivers over the course of the series. Following the first series, Dawe was replaced by May, and the hosting line-up remained unchanged until 25 March 2015, when Clarkson was informed by the BBC that his contract would not be renewed following an incident between himself and a producer. Following Clarkson's dismissal, his co-hosts Richard Hammond and James May, along with Andy Wilman, announced that they would not return to the show without him, and instead left to work alongside Clarkson to produce a new motoring series that would later be known as The Grand Tour. Following their departure, Chris Evans and Matt LeBlanc took over as the new hosts for the 23rd series, with Rory Reid, Sabine Schmitz, Chris Harris and Eddie Jordan joining them in the series when needed. Following negative feedback for the series, Evans resigned, with the BBC choosing to retain the other five presenters and assigning LeBlanc, Harris and Reid as the main hosts for the 24th series.
First-run episodes are broadcast in the United Kingdom on BBC Two and (from series 20) BBC Two HD. From series 14–19, before the launch of the dedicated BBC Two HD channel, new episodes were also simulcast on BBC HD. The series is also carried on cable television systems in the United States via BBC America, in Latin America via BBC Entertainment and in Europe and South-East Asia via BBC Knowledge.