Daphne Oram
Delia Derbyshire has received quite a lot of attention in recent years as a pioneer of electronic music, but Daphne Oram has been unfairly neglected. She was the one who persuaded the BBC to set up the Radiophonic Workshop in the first place - although the direction it took wasn't cutting edge enough for her, and she eventually resigned to work on her own music in a Kent oasthouse. This included inventing the Oramics machine, a system for converting pictures into sounds. "To me she was a kindly, rather eccentric aunt. But she had a very clear vision of how the computer would revolutionise electronic music," said her nephew in the BBC's obituary in 2003.
You can listen to some mp3s of her music or buy the CD here, and if you're in London, the Southbank Centre is paying a long overdue tribute to her next Friday. See you there.