You don't have to be a Whovian - or even know what a Whovian is - to enjoy it, but it wouldn't hurt to know that the title character of the show, which was revived in 2005 after a 16-year absence, periodically regenerates, allowing a change of leads. (If only "Law & Order" producer Dick Wolf had thought of this.)
Bradley is probably best known to American audiences as Hogwarts caretaker Argus Filch in the "Harry Potter" movies, though more recently, he told me in an interview last summer, "I seem to meet more people who've seen 'Game of Thrones' than anything else."
(If you haven't seen the most recent season of "Thrones," you might want to skip ahead a couple of paragraphs.)
And what has Bradley, who plays Walder Frey in the show, been hearing?
" 'Why did you do it?' " he said, grinning. " 'I can't forgive you.' "
Bradley doesn't seem to mind playing characters who are disliked, as long as they're interesting.
Filch and Frey aren't "drawn from the same genetic pool" but "they both enjoy being horrible," he said. "There's almost a comic pleasure in doing it. I like to think of Frey as being slightly funny.
"It's just not enough for me to play irritable pettiness, whether it's William Hartnell or Filch or whatever. You try and find a reason why they've got that chip on their shoulder."
He seems to have found it in Hartnell, a veteran actor who was initially reluctant to star in what was meant to be a children's program and who became a staunch defender of the show's integrity.
"Sometimes, he could be very difficult, and his illness prevented him from reaching the standards he demanded of himself, and he would get as irritated with himself as with others if they didn't come up to the professional standards he thought the show should have," said Bradley, who also thinks that Hartnell "slightly fell in love" with the much younger Lambert and reacted badly when she left the show.
"He found he was working with people who would say, 'OK, press that button to open the door, Bill,' in the scene and he'd say, 'But that button is over there.' And the director would say, 'What does it matter?'
"Of course it matters. Kids at home, they're cleverer than us. They spot things. If you press a different button for the same function every week, if you keep changing where the buttons are," they will notice, he said.
"William Hartnell respected his audience."
On Twitter: @elgray