The British series Dragons' Den was based on the Japanese programme Money Tigers.
Money Tigers established the central television idea of entrepreneurs seeking finance from wealthy businesspeople. The format was later adapted for different national audiences, with changes to the investors, branding, language and business environment.
The British version used the title Dragons' Den and introduced its own panel of investors, but retained the basic pitch-and-negotiation structure. This is why the UK programme belongs to a wider international family of business-pitch shows rather than being an entirely original British creation.
The name is easy to misremember because the British title replaces the Japanese programme's tiger imagery with dragons. It is also distinct from Dragon's Den in the singular: the UK programme is officially styled Dragons' Den, while Money Tigers is the specific Japanese source title.