Which original Dragon left the British TV show Dragon's Den after series 12?

Duncan Bannatyne left the British TV show Dragon's Den after series 12.

Bannatyne was one of the original Dragons when the British programme launched in 2005. He became known for his forthright approach to valuations and negotiations, as well as for his business interests in health clubs, hotels, care homes, and property.

He announced his departure in 2014, after completing his twelfth series. His exit marked the end of one of the programme's most recognisable original partnerships, although Peter Jones continued from the launch panel.

The timing can cause confusion because several Dragons departed in different years. Theo Paphitis left earlier, after series 8, while Bannatyne remained for four additional series. The answer refers to the original British panel, not to a guest investor or a Dragon from another country's adaptation.