Who became the first female investor on BBC's Dragons' Den?

Rachel Elnaugh became the first female investor on BBC's Dragons' Den.

Elnaugh was part of the original panel when the British version of Dragons' Den began in 2005. She joined Peter Jones, Duncan Bannatyne, Theo Paphitis and the programme's other original investors during its launch period.

She was known publicly for building Red Letter Days, a gift-experience company. The business later encountered financial difficulties, and Elnaugh left the Dragons' Den panel after its early series. Her departure helped make room for later female dragons, including Deborah Meaden.

Deborah Meaden is therefore not the answer to this question, despite becoming one of the programme's best-known female investors. Meaden joined in 2006, after Elnaugh had already established the first female presence on the British panel.