Mary grew up in Meopham in Kent. She was educated at Gravesend Grammar School where she gained a scholarship to Bedford College, London University in 1941 when the college was evacuated to Cambridge. She read Classics gaining an Honours degree. During that time she felt called to Missionary service and offered to CMS. However, they said teaching experience needed first. After receiving her teaching diploma she taught for two years at a Grammar School in York.

In 1947 Mary was accepted by CMS for training at Foxbury (then the CMS training college for woman). Like everyone else in those days her offer of service was for life and to wherever she was sent. After three terms she was sent to Bihar state in India .

Mary was in India from 1948 - 1979 and worked mainly with the Santal tribe.

Her gift for languages resulted in becoming fluent in Hindi and Santali and she also knew some Urdu and Sankrist.

She taught in St. Thomas's Girls School, Barharwa and ran the school's hostel. She also wrote and did translation work for both schools and the diocese.

Mary was by nature quiet and undemonstrative but those who knew her well enjoyed her wit and quick mind.

Her faith was deep and showed itself in her steadfastness and trustworthiness. She was one of a group of missionaries working in different parts of India who wanted to practice God's presence in their busy lives and, needing mutual support, they founded the Companies of Brother Lawrence in 1960. The idea spread to Africa and eventually to Britain.