Rachel Elnaugh was the only original female Dragon when the British series began.
Elnaugh joined the original Dragon's Den panel in 2005. She was known for founding Red Letter Days, a company that sold experience gifts such as leisure activities and special occasions rather than conventional physical presents.
Her business background made her a prominent early member of the panel. Red Letter Days later experienced financial difficulties and entered administration in 2005; fellow Dragon Peter Jones subsequently bought the business and assets.
A frequent mix-up is to name Deborah Meaden, who became the programme's best-known long-serving female Dragon. Meaden joined after the first series, whereas Elnaugh was the female investor in the original launch panel. The question concerns the initial cast, not the Dragon who remained on the programme longest.