Human rights, peace, social justice, fundamental matters of personal morality and the future of religion itself: no issue will be too small for the next pope, who will be chosen at a conclave of Roman Catholic cardinals that starts on Monday.

In what is perhaps the world's most extraordinary electoral process, a mere 115 red-hatted prelates with an average age of 71 will select the leader of a worldwide organisation that commands the allegiance of roughly 1.1bn people - one in every six human beings.