Who was the first female Dragon on the British series Dragon's Den?

Rachel Elnaugh was the first female Dragon on the British series Dragon's Den.

Elnaugh joined the original investor panel when the BBC programme began in 2005. Her place in the first panel made her the show's first woman investor, before later female Dragons including Deborah Meaden, Kelly Hoppen and Hilary Devey appeared in subsequent series.

Before television, Elnaugh was known as an entrepreneur and as the founder of Red Letter Days, an experience-gift business. That company became part of the business story associated with her public profile, although it is separate from her role as a Dragon.

The question concerns the first female Dragon, not the longest-serving female Dragon. Meaden later became the more enduring female presence on the programme, but she joined after Elnaugh.