Is it okay for Christians to vote for non-Christian politicians?

John Stevens is the National Director of the Fellowship of Independent Evangelical Churches, a family of over 500 Bible-centred churches in the UK, a position that he has held since 2010. John is also one of the pastors of Christchurch Market Harborough, a church he helped to plant when he took up his current role. He was converted whilst studying law at Cambridge University, and after taking a post-graduate degree at the University of Oxford worked for 16 years as a University Lecturer, ending his career as Deputy Head of the Law School at the University of Birmingham.