Rachel Elnaugh was the first woman to sit on the British Dragon's Den investment panel.
Elnaugh appeared as one of the five original Dragons when the British programme began in 2005. She was known for building Red Letter Days, a company selling experience gifts such as driving and leisure activities. Her entrepreneurial background helped define the range of business expertise represented in the opening panel.
Deborah Meaden is sometimes given as the answer because she became one of the programme's most recognisable female investors. However, Meaden joined after the original launch, whereas Elnaugh was present from the first series. Sara Davies and Jenny Campbell arrived much later still.
Elnaugh's tenure on the main programme was comparatively short, but her place in the original line-up makes her an important part of Dragon's Den history. The question concerns the British television version, not female investors in overseas adaptations of the format.