Jim al-Khalili is the son of a Muslim father and a Christian mother. He is also a public atheist - the outgoing President of the British Humanist Association - a science writer and broadcaster and Professor of Theoretical Physics at the University of Surrey. Here he talks to Abdul-Azim Ahmed about how his mixed-faith background has shaped his outlook on religion and atheism, and why he has no wish to convert everyone to the Humanist world view.