In BBC Dragons' Den, which former Dragon founded the Bannatyne Group health-club chain?

Duncan Bannatyne founded the Bannatyne Group health-club chain.

The Bannatyne Group developed into one of the United Kingdom's major health and fitness businesses, operating health clubs, spas and hotels. Bannatyne built the enterprise after earlier business ventures, including a successful care-home business, and became one of Britain's best-known self-made entrepreneurs.

He was an investor on BBC Dragons' Den from the first series in 2005 until 2014. His time on the programme made him familiar to a large television audience, but the Bannatyne Group was established independently of the show.

The company is often described simply as Bannatyne Health Clubs, although the wider group includes more than gyms. That broader corporate name is why “Bannatyne Group” is the most precise answer.