Deegan was born in London, England, where she trained in stage management at East 15 Acting School.
[2] Deegan is the resident writer for the prison, HMP Featherstone, where she teaches writing to inmates.
[3] Deegan is best known for Daisy Pulls It Off (1983), a comedy that which spoofs "schoolgirl novels" of the type written by Angela Brazil.
[4] The play was called a "pitch-perfect spoof" by The Guardian and it ran for three years in the West End theatre.
[6] Playwright and critic, Michelene Wandor, identifies Deegan's plays as feminist in nature.