Much to my surprise (I admit) ITV averaged 9.4 million viewers during the Big Debate last night. But we need to look at the numbers more carefully to see what was really going on throughout the full ninety minutes of play.

The first quarter-hour (I didn’t survive beyond this) was wooden with paint drying on the wood, so the audience was actually only 8.8 million.

As things got things a bit more unpleasant, some Twitter/text factor came into play, helping to add a further 700,000 viewers by 8.45…just as I was turning off.

The tweety-texty factor is heavily biased under 30, an age demographic that on the whole would rather eat cold cow-heel tripe than think about politics. Thus 400,000 of them too disappeared after fifteen minutes – post 9pm. I’d be willing to bet they don’t come back.

Scheduling by the other channels was also a factor, in that quite a lot of new arrivals tuned in around 9pm itself. The other channels had tried to hook people into an hour’s worth of something else from 8 pm, so that strategy seems to have worked. Only BBC2 decided to rise above such commercial vulgarity (they screened, perhaps ironically, a documentary about insects) while the others went balls out for the nation’s obsession with property and gory conspiracy theory: these were in turn The Big Build (BBC1) Country House Rescue (C4) and Nature Shock (C5).

The competition after 9pm was pretty ropey: repeats, a truly awful ‘comedy thriller’, two silly documentaries and an unfunny sitcom. And oddly enough, it was in the 15 minutes from 9pm that the additional million or more switched over. Most of them lasted about fifteen minutes (the same as me) and by 9.45 700,000 more viewers had tuned out – leaving the audience at 9.0 million by the end.

Let’s not be picky: 9.4million is a hugely impressive TV rating these days, although for Simon Cowell it would be something of an off-day. But before the politicos (and Nick Clegg especially) start seeing themselves as superstars, I think we should remember that a good footie game from 19:45 to 22:00 would’ve halved those figures. Further, the loss of audience towards the end must be worrying Mark Thompson, whose chaps managed to negotiate themselves into last place in the series. The rate of viewer loss during the final hour would, if continued in the next effort, see the audience level down to 7 million when the BBC’s turn comes. We shall see.

Only playing extra time after the ninety minutes would’ve given us a real steer on this. Personally, I favour deciding it with penalties. The Death Penalty was the one I had in mind. Now that would get the ratings up.