The British format of Dragon's Den usually features five investors on its panel.
These investors, known as dragons, listen to entrepreneurs present their businesses and then decide whether to offer money in return for an ownership stake. The panel format creates competition among the investors as well as pressure for the entrepreneurs.
The exact individuals on the panel have changed across series. Some episodes may also use guest or replacement dragons, but the standard British setup is built around five panel seats.
This fact is sometimes confused with the line-ups of other international versions. Different adaptations can use different numbers of investors, so “five” specifically describes the usual British format rather than every version of the franchise.