What is the UK title of the television format adapted as Dragon's Den?

The UK title of the television format adapted as Dragon's Den is Dragons' Den.

The British programme is part of an international franchise in which entrepreneurs present businesses to wealthy investors. The British title uses the plural possessive form “Dragons'” because the den belongs collectively to the panel of investors. In ordinary writing, the show is also frequently styled as Dragon's Den, especially in references to the UK series.

The format originated in Japan and was adapted for multiple territories. In the United States, the closely related version is known as Shark Tank, while Canada uses the title Dragons' Den. These titles describe equivalent franchise concepts but are not interchangeable as the UK programme's formal title.

The question concerns the format's UK title, not the name of an individual investor, a specific episode or an international spin-off. That distinction avoids confusing the franchise name with the names used in other countries.