Born on 13 April 1913 in Whitby into a staunchly Methodist family with ancestors who had entertained John Wesley, Mary Foster read English at St Hugh's College, Oxford, where she was a founder member of the John Wesley Society, came under the influence of Harold Roberts and became a Local Preacher. She taught in girls schools, before marrying Arthur Lenton (1915-2009), born on 30 March 1915, in 1940. He was the son of a Methodist minister, W. Arthur Lenton (1876-1964; e.m.1903). Arthur had been a Classical scholar at Oriel College Oxford and taught at St Bees School before becoming a Conscientious Objector during World War II, when he served in the ARP in Portsmouth.
From 1946 Arthur and Mary were tutors in child care at the Princess Alice College, Birmingham. She fully supported him in his role as Governor of the Birmingham Branch ofNCHO from 1948 and was elected that year to Conference, where her speech in the Conversations debate at Plymouth in 1965 was particularly influential. They moved to London from 1968 to 1980, where Arthur was Development Officer at NCH headquarters, helping to transform NCH buildings to meet the new challenges of the late 20th century. Mary taught in a secondary school for 5 years, became chairman of Women's Fellowship, a governor of Southlands College and the first woman treasurer of the General Purposes Fund. She served on the President's Counciland was Vice-President of the 1978 Conference. The welfare of children, spiritual growth, worship and Christian reunion were foremost among her concerns.
They retired to Whitby in 1980, where they continued to preach, Arthur acting as Circuit Steward. She died on 27 June 1998; he died 25 March 2009, both in Wellington, Shropshire, where they had moved to be near their son.