In the 60s, Derbyshire worked for the BBC Radiophonic Workshop, which was essentially the sound effects department of the BBC. She was fascinated with music and the mechanics of sound, and had previously tried to get a job at Decca Records only to be told that women weren't allowed in the recording studios (Decca was also the record company that turned down the Beatles; talk about a company that couldn't recognize talent.) Derbyshire didn't actually compose the theme (that was done by a man named Ron Grainer) but she was responsible for setting his notes to music. The story gets even more intriguing when you realize how this was actually accomplished in a period before commercial synthesizers were readily available. It was a complicated process at the time which involved a lot of cutting, splicing, speeding up and slowing down fragments of analogue tape. Honestly, I read about what Derbyshire did on this Wikipedia page and couldn't make heads or tails of it. Let's just say she was extremely clever. When Grainer heard the finished product for the first time his astounded response was, "Did I write that?" to which Derbyshire responded, "Most of it."
Every time the show came on PBS while I was a child, the theme gave me the chills. I was not the only one--apparently the BBC received complaints from at least one parent who said their son was terrified of the opening music. And yet, it's also strangely hypnotic. I can't think of a more appropriate, freaky TV theme for a sci-fi show!
Derbyshire was truly a pioneer of electronic music and would go on to have a lucrative career experimenting with music and producing scores for the theater and movie soundtracks (you can look up her work on YouTube) but the Doctor Who theme will always be her most famous piece. She deserves our kudos. Thanks, Delia, for freaking me out as a kid!