From BBC Online

As Doctor Who fans celebrate the series's 50th anniversary Dr Andrew Crome, lecturer in the history of modern Christianity at the University of Manchester, explains how the time-travelling Doctor allows us to explore different beliefs and ethical viewpoints.

A near immortal crossing space and time, followers split over interpretation, characters in strange hats... Perhaps it is no surprise Doctor Who is sometimes described as a form of surrogate religion.

However, behind this light-hearted comparison lies a grain of truth, as Doctor Who has continually engaged with important religious themes across its 50-year run.

At times religion has been addressed directly. For example, 1970s producer Barry Letts, a practicing Buddhist, worked ideas from his faith into the show's narrative: witness Jon Pertwee sharing a version of the Mumonkan's sixth Zen Koan with companion Jo Grant in the 1972 episode The Time Monster.

http://www.bbc.co.uk/religion/0/24924746