Dragon's Den first premiered in the United Kingdom in 2005.
The BBC began broadcasting the British adaptation on 4 January 2005. The programme brought entrepreneurs into a studio to seek investment from a panel of wealthy business people, with the founders required to defend their valuations, sales figures and proposed equity deals.
The British series was adapted from the Japanese format Money Tigers. Its first season established the visual and editorial conventions that became familiar: a founder enters the room, states the requested investment and gives a pitch before the Dragons question the proposal.
The year is sometimes confused with the dates of later international adaptations or with the launch of the American programme Shark Tank. Those are separate productions. The UK programme's debut belongs to the mid-2000s, and 2005 is the specific year in which the BBC version began.