Duncan became a Christian in his late teens when he was at boarding school, shortly before leaving to go to university at Oxford to read classics. Duncan was deeply impressed by the godly witness of his school headmaster and he made a personal commitment to Christ when he went to a Christian conference at Wycliffe Hall.
Duncan has been a lay member of the General Synod of the Church of England and his on the Church of England Evangelical Council. Duncan believes wholeheartedly in the Bible and the 39 articles and laments the departure of the current Anglican Church from her doctrinal foundations. Duncan is a barrister (by training) and the owner and director of a property company. He is married to Alexandra and divides his time between London and Somerset. When in London they worship at All Souls Langham Place.