Doctor Who writer Toby Whithouse promises a "more dangerous, volatile, unpredictable" Doctor

And this Saturday, in western adventure A Town Called Mercy, it looks as if the Doctor could suspend his pacifist ideals again as he is forced to use a gun.

Toby Whithouse, who penned the episode, said viewers could expect a “more dangerous” Doctor than usual.

"To write him as a slightly more kind of volatile and unpredictable character was really refreshing and exciting," said Whithouse.

A Town Called Mercy pits the Doctor against a cyborg cowboy, Isaac (played by Farscape’s Ben Browder), and sees the Time Lord turning gunslinger himself.

"The sequence where the Doctor is kind of forced to use a gun - giving the right sort of emotional journey to that took a lot of finessing. That was the scene that, from draft to draft, would change the most regularly because the Doctor is a confirmed pacifist,” Whithouse told SFX.

“Putting him in that situation is a wonderful opportunity in that it forces you to confront [that pacifism], and provides you with enormous tension and drama which, as a writer, is what you want."