Dragon's Den originally aired on BBC Two before moving to BBC One.
The programme launched on BBC Two in January 2005 as a British version of a Japanese business-pitching format. Its early episodes established the familiar formula: entrepreneurs presented their companies to investors, answered detailed questions and hoped to secure a deal.
The later move to BBC One reflected the show's growing popularity and gave it a larger mainstream platform. BBC One is the BBC's principal general-interest television channel, while BBC Two has traditionally carried a strong mix of factual, arts and specialist programming.
The channel history matters because some viewers remember only the programme's later home. It did not begin on BBC One, and BBC Three and BBC Four were not its original broadcasters. The move was a change of channel, not a change in the basic concept or the programme's title.