In 1945, she moved to Bedford College, London, as a lecturer in physics. She spent 10 years there, gaining her PhD and working in the fields of relativity, quantum mechanics and electromagnetic theory. At Bedford she was involved not only in the physics department, but took a great interest in the administration of the college.
In 1955 she was appointed Principal of St Mary's College, Durham.
She was invited to become Principal of Royal Holloway College, University of London, (RHC) in 1962 following the resignation of Dr Edith Clara Batho. Before Williamson became Principal, RHC admitted only women as undergraduates and offered a relatively restricted number of courses. Men were only admitted as postgraduates after 1945. Because of this, and its situation in the outer London suburb of Englefield Green, Surrey, the RHC was seen as something of a backwater.
Williamson set out to change this image by admitting men undergraduates and by a comprehensive expansion into new buildings and academic disciplines. She provided a new Students' Union building and revived the religious life of the college by the appointment of four honorary chaplains.
By the time she retired as Principal in 1973, the college had admitted men as undergraduates since 1965 and expanded into new buildings, and staff had been recruited for new departments such as biochemistry, statistics, computer science and music .
On leaving Royal Holloway, Williamson moved to a small village in Warwickshire, where she was a valued and popular member of the community, taking a close interest in village life and acting as a volunteer for the National Trust at nearby Charlecote Park. She moved again in 1985 to a converted barn in Suffolk, near a lifelong friend, Ann Thomson, also a graduate of Royal Holloway. She died, unmarried, in 2002.
- Who Was Who - subscription based - accessed 29 July 2011
- The Guardian, obituary, 31 August 2002, accessed 27 March 2009
- Obituary in "The Independent", London, 31 August 2002, by Janet Knight
- Royal Holloway College official obituary including picture
Dr Edith Clara Batho
Royal Holloway College
University of London
Dr Lionel Harry Butler