Three divided by zero...

"No, I wouldn't consider closing a channel.... we have to find other ways of prioritising".
Tony Hall, BBC Director General, October 2013

I'm a BBC Four person, frankly. I suppose I should be relieved, delighted even, that my channel's survived, and the other one's for the chop.

But the hasty, poorly-explained decision to get rid of BBC Three worries me. It's been rushed, and it could have a huge impact on the BBC years, maybe decades, from now.

It's easy to lay into a channel you never, or hardly ever, watch. I bet you hardly ever listen to Radio 1 either. And BBC Three is just as important to the survival of the entire corporation.

The BBC is very, very good at over-serving middle-aged, middle-class, metropolitan people. We get BBC Two, BBC Four, and Radios 2, 3, 4 and 6. Frankly, for the likes of me, our license fee is a spectacular bargain.

But it's a bit different if you're 25. You get Radio 1, bits of BBC One, and BBC Three. And now, the only BBC channel aimed at you is being shut on the orders of people twenty or thirty years older than you.

Why does that matter? Because the BBC risks losing touch with an entire generation.

Bye-bye, the youth. Don't forget to come back in 20 years...

Bosses admit 75% of current viewing by BBC Three's target audience is to live TV. Not iPads, or mobile phones. Old-fashioned televisions. Even though that's likely to change, TV will still make up 60% of youth viewing years after BBC Three has vanished. The BBC is voluntarily surrendering a huge chunk of its youth audience, and just hoping they'll somehow keep them online.

Let's be clear. BBC Three is being axed. A handful of "youth" programmes will be thrown online, and repeated a few days later at 11pm on BBC One. That's not a TV channel. 

And the "savings" are being handed to BBC One, to make more mainstream drama. Just the kind of thing the average 25-year-old enjoys watching.

Meanwhile, the space freed up by axing BBC Three will be handed to BBC One +1. Innovative? Not exactly.

Right now, BBC Three occupies a prime slot on every television in the UK. Online, it becomes one of a thousand voices, screaming for attention.

But you don't watch BBC Three, so it doesn't matter to you, does it?

Let's leap forward for a moment to 2025. Ten years after the planned closure of BBC Three. The Corporation's Royal Charter is once again up for renewal.

But now there's a large, and growing, section of the audience that simply doesn't engage with the BBC. The audience abandoned by BBC Three ten years earlier.

Now in their thirties and forties, they never really saw the BBC as anything different from ITV, Sky 1 or E4 -- the only difference is they have to pay for it.

How do you justify a universal tax, if you don't provide a universal service?

Like Radio 1, BBC Three brings public service broadcasting to the next generation of licence payers. It builds on the relationship with the BBC that starts in childhood, keeps the Corporation relevant to people as they move into their adult lives.

Under this plan, the BBC will abandon this generation when they turn 15, hand them over to rivals, and hope they'll somehow drift back to the BBC when they're older.

But all the while, demand they keep paying the same annual fee, to support all those other channels they rarely or never watch, and which aren't actually aimed at them.

You don't watch BBC Three? You should still care about it being axed...

BBC Three has been the creative engine of the Corporation for the last decade. A place to experiment, in front of reasonably big audiences. Some experiments fail. Others succeed wildly.

But in future the next new writer, working on the next new hit, will probably take it to Channel 4, or Sky, maybe even ITV2. That's very, very bad for the whole of the BBC.

The people who run the BBC today effectively hold it in trust, on behalf of all of those who pay for it. They have a duty to hand it on in at least no worse a state than it was in when they inherited it. 

This rushed, and on paper easy decision, could create creative and political problems that come back to haunt the BBC for years to come.