The mistake of both films is not to include a dissenting or questioning voice. The fact that the soldiers held responsible for the abuses at Abu Ghraib were prosecuted and served time is certainly made very clear in the superior Standard Operating Procedure, but could not the point also be made that it is this fact, and indeed the very existence of films such as this, that separates us from those we might be fighting against? That would, of course, reduce the stock of indignation, but, rather like the now famous pro-war speech in David Hare's otherwise righteously anti-war play Stuff Happens, it might give an on-side audience something unexpected to ponder. Polemics - and in all essentials, that is what Taxi to the Dark Side is - can be invigorating, but they really shouldn't masquerade as documentaries, especially when, as here, they appear not to be "authored". At least Michael Moore, like John Pilger before him, puts himself bang up front in his own films, in the spotlight, even if he does spend the rest of the time running away to hide from the intrusive eyes of the media.

But that is the way it is with current mainstream factual feature-making, and there's no reason to expect it will change. What we need is a Taxi to the Bright Side. So where are the centre-right documentarians and polemicists? There is, after all, nothing worse than going to a party only to stand in the kitchen and slag off the other guests. It is not good enough, and simply not true, to suggest that conservatives prefer the printed word to film. Isn't it time there was a feature-length documentary on the world-wide growth of Islamism, which didn't just creep out via the internet? Or a major, Oscar-worthy production telling the true story of Stalin's Terror? -(Astonishingly, there hasn't been one.) Perhaps, even, a rightwing Michael Moore? You might lose one audience, but there'll be a whole new one to gain.