In an interesting example of parallel evolution, at about the time Western movies were taking off in America there was a similar genre burgeoning in Germany: bergfilme or mountain films. They were not afforded the time to flourish or to develop any formal complexity or tradition of romanticism because, in the thirties, they fell foul of the Nazi regime’s predilection for censorship.

Ironically enough Hitler did eventually come to admire mountain films and their mythologising of self-reliance but this late conversion merely accelerated the extinction of the genre. The post-war taint of Nazi affiliation was too much to overcome.

One of the finest examples of a bergfilm is Dr. Arnold Fanck’s The Holy Mountain (1926). This tale of two mountaineers both in love with the same woman could be trite enough but, as with Westerns, the desolate nature of the landscape in which the story takes place makes any systematised morality redundant. A new morality emerges which is personal rather than imposed by social conventions, and is all the more interesting for it. If you haven’t seen The Holy Mountain please give it some consideration. It is an amazing film.

The photography is entrancing. The movie was filmed for real in the Alps over a whole year. And the woman at the apex of the love triangle is enchanting too: eerily beautiful, and not emotionally straightforward. She was played by the twenty-four year old Leni Riefenstahl. At the time Riefenstahl was an actress and interpretative dancer but she went on to become a filmmaker of considerable technical virtuosity.

She directed and starred in the peculiarly slanted fairy tale The Blue Light in 1932, but she is principally remembered for her documentaries made for the Third Reich: Triumph Of The Will and Olympia. The repugnant nature of these films’ subject matter inevitably left more of an impression than her directorial skill and in the aftermath of the war she found her reputation permanently tarnished.

Through her life Riefenstahl actively sued for libel anyone who accused her outright of Nazi collaboration. The creative urge behind her most infamous works was, it became widely accepted, aesthetic rather than political. During the seventies there was a partial rehabilitation for her as she photographed the 1972 Olympics in Munich and was feted as a guest of honour at the 1976 Montreal games. And although she lived to the age of 101 (dying in 2002) indefatigably unapologetic and apparently having lived a full and happy life, her name still carries deeply unpleasant associations to anyone of any sensitivity.

If you fly with the crows, you get shot with the crows. And the same happens, I’m afraid, if you step with the geese.

It is hard not to burden her youthful beauty with the emotional freight of everything that came afterwards. It can all make for a very difficult and ethically provocative wank.

But as the tradition of mountain films fizzled out before establishing itself, westerns continued to flourish.

It is possible to see now in the Westerns of the thirties through to the sixties abiding themes of emergent personal moralities. Stagecoach, High Noon, The Searchers, Rio Bravo, The Naked Spur, The Man Who Shot Liberty Valance all show in one way or another and to greater or lesser degrees, what it is like to be an individual with a dilemma, but without societal constraints or the mitigating effect of a civilised environment.

These frontier narratives are about the development of a coherent and tolerable sense of self, and up to this point it makes sense to regard cowboy films or Westerns as a consistent genre.

This ceases to be the case in the sixties I think when the influence of spaghetti westerns, particularly the sordidly beautiful ones of Sergio Leone turn the Western from a philosophically enquiring form into ostentatious theatrics.

This isn’t to say the Leone films and their orbiting satellites are bad or unworthy in any way. They aren’t. They are fucking magnificent. But they are less rooted in personal responsibility and growth, and more excited by the trappings of Grand Guignol, the stating of moral certitude and a rudimentary narrative balancing of accounts.

The choices of emphasis in something like Once Upon A Time In The West for example have more in common with Mario Bava’s Bay Of Blood or Dario Argento’s Deep Red than they do with Shane. In fact Argento even shares a story credit for Once Upon A Time In The West.

There were far fewer Westerns made during the seventies than in previous decades, and many of those that were released seemed less bothered about frontier morality and more concerned with how an individual fits into the wider world whose encompassment has become inescapable. As perhaps you might expect from an anxious superpower still stinging from its disastrous involvement in a land war in Asia.

“Sometimes trouble just follows a man,” says Clint Eastwood during The Outlaw Josey Wales (1976), in which he is playing a man who seems fundamentally to want to be left alone but who cannot escape the company of others.

There were still Western stories being told, but more often they were in what seemed to be other genres. Dirty Harry, Chinatown, The Long Goodbye, Alien, The Thing all have the traditional Western ethic at their hearts.

Films of the eighties onwards that looked like Westerns (Silverado, Dances With Wolves, Unforgiven, 3:10 To Yuma) may be terrific films, but they are made by people concerned with the craft of making a cowboy film rather than people with a new thing to say in a Western framework.

This is all a terribly long-winded way of saying that not every Western has people with cowboy hats in it. And not everything with cowboy-hatted people is a Western.

One can see this quite clearly in any Western/fantasy genre mash-up.

At their worst they can be pretty ignoble spectacles, the sci-fi Westerns. The Valley Of Gwangi, Tremors 4: The Legend Begins, Jonah Hex, The Burrowers, Cowboys and Aliens. These all make quite steep demands of the casual viewer. And even the good ones like The Seven Faces of Doctor Lao or Billy the Kid vs. Dracula are principally genre pieces with cowboy clothes on rather than Western movies per se.

Back to the Future Part III for example is a glorious piece of work just quivering with glee, but it would be a brave and heterodox critic indeed who stuck it on a list of the greatest Westerns ever made.

And where does Doctor Who stand in all this? Preserver of the western tradition, sci-fi nonsense in a ten-gallon hat or something else?

Prior to A Town Called Mercy the programme’s only notable dalliance with the genre was the 1966 William Hartnell story The Gunfighters. This is the story in which The Doctor, Dodo and Steven become embroiled in the events leading up to the historic gunfight at the O.K. Corral.

The Gunfighters has had quite a shabby reputation in the cardboard corridors of Doctor Who fandom for as long as I have been watching the show. It does now seem to be going through some process of rehabilitation into society thank goodness, and (partly at least because of the attentive DVD release it got in 2011) it is finally accreting a number of proselytes. Of whom I am one.

It is easy with any telly programme dating back forty-six years to have a bit of a snark at the production values, but this is horribly misguided in the case of The Gunfighters I think. It is a plucky little series. There is just something majestic in the idea that it would be advisable, or even possible to create a four-episode cowboy story entirely within a British studio.

The only other contemporary British Western I can bring to mind is Carry On Cowboy (1965), and even that allowed itself the freedom of some location shooting to alleviate the studio claustrophobia.

Furthermore The Gunfighters is admirable in sticking pretty closely to what, if they aren’t actually the facts, are the accepted movie-truth version of events. It is still part of Doctor Who’s, by then waning, commitment to pure historical stories with no science fiction overtones at all.

Finally, I find its jamming together of broad comedy (Peter Purves in particular absolutely nails it) and brutal, fatal reality to be in every way laudable. Tonal consistency is an ambition for lesser minds. Bring on the creative dissonance, I say.

Toby Whithouse and Saul Metzstein, the writer and director of A Town Called Mercy respectively, both seem aware of The Gunfighters and reference it deliberately several times I think: the use of narration, the confusion between our Doctor and another Doctor (Doc Holliday and Kahler Jex), the Doctor’s becoming a deputised lawman, and the shiftless locals in need of moral authority.

Saul Metzstein’s direction of A Town Called Mercy is simply magnificent. The Almería location may do some of the work for him, but the Leone-esque frame filling is his entirely. Murray Gold’s music helps a great deal too, channelling both Bernstein and Morricone at times whilst maintaining his own musical idiom. Murraycone.

As always though Who stands or falls on its actors and we are in safe hands here. Matt Smith’s comic abilities are beautiful. I could have done without some of the script’s seeming heavy-handedness (leave the bag in, a horse called Susan and so forth) but Smith can pull just about anything off. Getting up after being thrown to the ground. The business with the tooth pick. The alien car alarm. It’s all in Smith’s performance. And he’s becoming great at doing Hartnell-hands as well.

I love his spindliness and his big flat, pink face like a chatty shovel with a hat on. But I love how quickly he can take it down to sinister, solitary menace too.

Toby Whithouse’s script is clever. It is nice to see a conflict in which it is not really clear who is the protagonist and who is the antagonist. And it is rare for so convincing a moral equivalence to be drawn between the Doctor and the, for want of a better word, baddie.

The resolution is smart too, and morally sophisticated. The notion that one inevitably pays for one’s trespasses in some form or another is a mature one. The hope that the people one needs to make amends to will be kind is a beautiful one. More of this on a Saturday night, please.

The companions seem to be very much in the background in A Town Called Mercy. Rory’s input is confined to some funny business acknowledging the tertiary nature of his role in proceedings, and Amy is only really called on towards the end of things when she is required to talk the Doctor down. This is thrilling to watch and is a major step forward in the depiction of Amy and in Karen Gillan’s interpretation of the role.

There is foreboding at the start of the episode when Amy seems to point out that the Doctor suffers when he travels alone. We have been here before. Donna Noble noticed it in Ten’s era and look how that ended up.

The companions also take one more tentative step down the road to ultimate divorce from the Doctor at the end of the episode when they decline to come with him on another adventure. And whilst part of me does sort of want to know what happened to the dogs and chimps that got blasted into space, most of me accepts that this is like Holmes’s giant rat of Sumatra. A thing more exciting to wonder about than to see made specific.

Amy’s reason for not going with the Doctor is that their friends are going to start noticing that they are getting older faster than them. This is a particularly exquisite Toby Whithouse grace note, and he has touched on it before in his 2006 story School Reunion . That was the story in which the actual alien invasion plot was entirely subordinate to the notional subplot: that of Sarah Jane meeting her Doctor for the first time in thirty years. That packed a massive emotional wallop. I am beginning to suspect that the Ponds’ leave-taking may actually be as gruelling as Steven Moffat has been suggesting for some time.

A couple of things to mention that don’t really relate to anything else: Firstly, that’s two weeks running that the Doctor has mentioned his Christmas list; secondly, the Henry VIII en suite phone-charger incident, is that before or after the parson’s nose affair?

Before leaving A Town Called Mercy altogether, there is one final parallel to draw between this episode and The Gunfighters: that being the use of narration.

In the latter the narrative voice is Lynda Baron singing Tristram Cary’s Ballad of the Last Chance Saloon. This is slightly overpowering when the programme is watched through in one go but as a weekly contextualiser, which is what the song originally was, it is a witty and effective solution to a tedious problem.

The narrator of A Town Called Mercy is slightly more enigmatic than Lynda Baron. Not appearing as a character, she is finally revealed to be the great-granddaughter of a young girl who is at best ancillary to events. This is puzzling.

Does it make the narrator a contemporary of ours? If so will she become a character, or is this just part of the season’s theme so far of removing the Doctor from the centre of events and making the story about someone else, like Oswin or Brian? We may find out later.

Her early references to “…a man who lived forever but whose eyes were heavy with the weight all he’d seen, a man who fell from the stars…” are cheekily misleading. But the references to America being a land of second chances are peculiarly specific and seem to have their origins in George W. Bush’s State of the Union Address in 2004.

Can this be right? Casting Richard Nixon in a half-light of approbation was one thing, but Dubya? That would be amazing.

Get Josh Brolin’s agent on the phone. Now.

Next week, God help us, it is this. I wear pants now. Pants are cool.