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

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

Bannatyne was one of the programme's original investors and became known for his outspoken questioning and interest in businesses with clear commercial potential. He departed after the twelfth series, ending a substantial run on the panel while the programme continued with other dragons.

His television role followed a broader entrepreneurial career. Bannatyne built businesses in areas including care homes, health clubs and hotels, and he became a familiar business personality in British public life. His background gave his Dragon's Den decisions a practical focus on growth, costs and the ability of founders to execute.

The other choices were also associated with the programme, but they did not leave after series 12 in the same way. Panel changes are easy to confuse because the BBC has rotated investors across different eras, so the series number is the key identifying detail here.