Year 10: It’s 8am on Wednesday morning, and Half-wit has been called to the diary room. The news is not good. After the initial novelty, he is informed by the anonymous interlocutor, the public has grown weary of his antics and everyone thinks he should leave. But Half-wit is not as dumb as he looks, and knows something about how to work an audience. Surely, he replies, having me around contributed something to the national conversation?

Half-wit, of course, is not the talkative housemate from this year’s reality TV show Big Brother, but the Channel 4 executive who kept commissioning it in the first place. Next year’s series of Big Brother, Channel 4 announced on Wednesday, will be its last. The show, said its director of television, Kevin Lygo, “had reached a natural end point on Channel 4 and it’s time to move on”.

Unlike some of its most popular housemates, it is unlikely that there will be much cheering for Big Brother on the outside. A few of its contestants were charming enough, but most were self-made nothings competing with each other to live out doomed fantasies of a celebrity career. If this is what it means to have a national conversation, it would be better to have none at all. But what was it that finally killed Big Brother? At least when it launched, with its live-streaming on the web and its interactive voting, the show could boast that it was ahead of the technological game. It was also riding a cultural wave.

For all their claims of authenticity, however, shows like Big Brother were always tightly edited artifices created by professional television producers in which anything interesting was bleeped out or banned. On the day before Channel 4 announced it was axing the programme, Big Brother instructed this year’s housemates to “do something entertaining”. When their very reasonable response was to stage a mass break-out, the programme-makers responded by telling them they’d forfeited the £100, 000 prize money they usually divvy out to the winner.

With killjoy producers like this, it’s no wonder that the Big Brother game was up. In any case, by this time we’d discovered something a little less artificial and didn’t want to go back. As broadband connections became widespread and opened up a permanent window on to the web, many of us zoned out at work or disappeared off to the spare room to spend hours peering at and sending messages to each other online.

In retrospect, the alliances forged between CCTV and broadcast television in shows like Big Brother seem like a fuzzy prototype for a world in which many of us would prefer to spend our leisure time hooked up to places on the net where we could ogle our peers. Faced with a clumsy, inane national conversation, many of us have opted to talk amongst ourselves instead on webcams, blogs and Twitter. At the beginning of 2006, for example, I visited a brand new high-tech project called Shoreditch Digital Bridge in east London, whose purpose was to bring to two socially impoverished urban estates access to broadband and digital television, which their residents might not otherwise be able to afford.

Almost as an afterthought the architects of the Shoreditch project had decided to offer residents access to images from a range of CCTV cameras that monitored the communal areas of their estates. In preliminary discussions, the manager of the project told me, none of the residents were remotely bothered by the implications for their privacy. Most, in fact, were highly enthusiastic. Some justified their interest in the CCTV as a crime prevention measure, but others admitted to a more prosaic reason for wanting to be surrounded by cameras – simple curiosity. They weren’t kidding.

By November 2007, according to an internal report commissioned by local government, viewing figures for the scheme were as good as that for prime-time, weekday broadcast television. More residents had tuned in to watch each other on CCTV than had bothered to watch Big Brother.

As the decade progressed, Big Brother couldn’t really compete with an army of little brothers watching each other online. It doesn’t stop the television schedulers from trying. This morning, delegates arrive for the first day of the annual Edinburgh International Television Festival. Half-wit and his friends will be out in force, thinking up an indigestible gruel of shows which rely heavily on interactivity, CCTV footage and audience-participation spectacles like Strictly Come Dancing and The X Factor.

After the death of Big Brother, however, the mood is likely to be a little gloomy, not least because the show is a microcosm of the parlous state of British television. Aside from the odd jewel – Jimmy McGovern’s The Street, The Red Riding Trilogy – prime-time TV has become a ghostly presence in which talentless has-beens roll past to remind us that they still exist. It’s no wonder that, even when we’re watching them, many of us have one eye elsewhere.