Doctor Who: Every Doctor's First Episode Ranked Worst To Best

The Power of the Daleks introduces the concept that the Doctor can change their face by "renewal", but doesn't get bogged down in the minutiae of how the process works.

Instead, it kicks into gear with one of the greatest Dalek stories of all time. David Whitaker's Dalek scripts are always a joy, because he writes them not as unthinking robots, but as sneaky, manipulative aliens. Here, they position themselves as compliant servants, but they're secretly plotting against everyone on Vulcan.

It was a genius move to pit a brand-new Doctor against the Daleks. After all, between 1963 and 1965 they were arguably the biggest stars that Doctor Who had produced. Bringing them back for Patrick Troughton's first story means that the pressure is taken off him as he finds his feet.

Not that Troughton wastes any time – he's instantly charming as the Second Doctor, retaining the impishness of Hartnell's incarnation, but dialling it all the way up.

Many Doctor Who actors say they don't feel like they've "arrived" until they face the Daleks. Troughton does that on day one, and the rest is history.