Pettitt was born in 1947 in Ulverston in the Lake District, England.
[1][2] She studied English at the University of Bristol, then squatted in the East End of London from 1969 until 1977, working as a teacher and a legal clerk.
She moved to a smallholding in Llanpumsaint, Wales and participated in the anti-nuclear movement.
[1][3][2] After reading a newspaper article about the USA putting nuclear cruise missiles at RAF Greenham Common in Berkshire, England, Pettitt was outraged and decided to organise a march to the base from Cardiff.
Since she had her life and family in Wales, Pettitt did not live at the camp and last visited it in 1984.