Click here to watch the trailer for Attilla the Hun

There should be a new category of acting, really. We already distinguish between theatre work and film work; support and lead; character acting and being a “star”.

To these divisions, then, I would like to propose one more: Pirate Acting.

I would like to make it clear that Pirate Acting does not simply cover all film depictions of pirates. For example, despite playing a pirate in Pirates of the Caribbean, Johnny Depp does not do Pirate Acting in that film. His Captain Jack Sparrow - while having an instant, cartoon-like iconoclasm - also has a supple, multi-referenced, postmodern vulnerability to it. An almost omnisexual fluidity, if you will.

Pirate Acting has none of that stuff in it. Pirate Acting is primarily about three things: a) rolling eyes 2) big teeth 3) SHOUTING. Although 4) - charging at things going “ARGGGGGHHHHH!” - is a very useful adjunct. If some Pirate Acting saw some omnisexual fluidity, it would roar “AVAST! Some dirty SON OF A SEA-BITCH has spilt some OMNISEXUAL FLUIDITY on my POOP, and if it's not SWABBED OFF BY SUN-DOWN, I'LL RENDER HIS BODY-FAT DOWN INTO SHOE POLISH, AND USE IT ONLY TO SHINE UP THE BOOTS OF GAY MEN! ARRRRGH!” Even if the actor in question were playing a repressed butler on Cranford at the time. Or, indeed, not actually working - just picking up a loaf, from Greggs.

And so to Attila the Hun. Of course, as an hour-long TV biopic of one of the most famous warriors in history, one is not expecting too many tearful, finely nuanced exchanges from the Huns. They spent most of their time running across Europe, setting fire to it, and roasting hogs on the embers, which they then ate with their hands. It's not going to be On Golden Pond.

Instead, we have - as one would expect - some manner of Pirate Acting Olympics, with Huns, Scirians, Visigoth, Astrogoths and Franks all screaming at each other during a series of high-camp face-offs.

Attila is played by Rory McCann - previously the big man in the kilt in the Scots Porridge Oats advert - in a summation of the big man's big battles that's short on script, long on blood, even longer on “ARGHH!” In the same way that heavy metal bands write a few ballads, to mollify their weary fans' girlfriends, Attila provides nugatory human interest with Attila's dwarf. Not in the show for long, the dwarf - who functions as camp jester - is notable for one thing: the worst reception ever accorded to a comedian in history. Fifteen minutes in, while doing a bit of patented capering, the dwarf tells a joke so bad Attila stands up and kills his brother. It makes a slow hand-clap at Jongleurs look positively benevolent.

Aside from the dwarf-inspired stint as the Dark Ages' Simon Cowell, however, Attila has little left to do except keep his long, Neil Young hairdo mysteriously clean, and kill thousands of people. For the most part, McCann simply points his teeth at a scene, screams “ARGH!”, and lets the enamel take the strain - occasionally pivoting his eyeballs if something particularly immense happens to him, like being shot in the liver with an arrow.

The thing is, though, the people aren't the point here. Emotions aren't particularly relevant. Even Attila - despite the grave-eyed assurance at the start, that this re-creation has been “written with the advice of historians”, rather than rugby players, or cats - is a bit of an adjunct. The big thing about Attila is the battles - rendered in Lord of the Rings-type widescreen, with the best CGI effects you have ever seen on a TV show.

Personally, I'm a bit of a gigantic CGI battlefield wonk. And while this isn't, obviously, quite up there with 300 or LOTR - no big score, no elephants, no wizards - it is, for a supposedly “educational” programme from the BBC, going to make a lot of teenage boys newly interested in the dying days of the Roman Empire.

After all, what can you say in the face of an exquisitely rendered panning shot of 100,000 Roman soldiers, camping by the Rhine, helmets glinting in the sun?

Except “ARGHHHHHHH!”, of course.

Attila the Hun, Wednesday, BBC One, 9pm (Scotland, 10.45pm)

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