I have academic friends who don't watch telly. They may have lives of endless interest, acting out scenes from Dickens (with all the voices) or drying wild flowers while sipping sherry, but I have no idea what they do when they are at home, nor do I care. I have other friends who watch television endlessly who complain that it's all rubbish, that every programme is cheap reality TV, while never missing an episode of any of it.
I fall somewhere between the two. A TV-generation child, I learned my ABCs from the "box" and have vivid memories of watching it at my grandmother's house, transfixed by Jackie Pallo and Mick McManus battling it out in the wrestling ring every Saturday. My grandparents had a market stall and the TV was the first real piece of home technology a working-class family such as theirs could afford. I remember going to a rather dull middle-class friend's house after school once and being told that they didn't have a TV as it ruined the mind and corrupted the soul. I never went there again. Yet such snobbery persists.
I like the comfort of the box (flat screen nowadays) with its 500 channels, many of which are called "Dave" or "Shed" or "Living", and its menu of programmes showing viewers how to go carp fishing up the Orinoco, find that bargain at a car-boot sale or turn a horrible semi in Rotherham into a palace using two teams of volunteers and things found in a skip. Afternoons are a cornucopia of such fascinating tat, but this televisual pollution is not entirely to be dismissed. After all, it's what makes up most television production.
As usual, we can lay the blame at Maggie Thatcher's door. Her liberalisation of broadcasting meant that old monopolies were broken and new televisual treats could be formed.
In a sense, TV had come of age and the technology, once so expensive, was now relatively cheap, accessible and open to all. The multiple channels that sprang up overnight were seemingly democratic and paid for by the cheap advertising of loan companies and injury lawyers touting for business.
Yet liberalisation came at a price. The trio of old channels (with Channel 4 and Five bringing up the rear) could not hope to produce the amount of TV programming that all the other channels would need to fill their remits. These smaller channels would have to rely on quick, cheap programmes of a new sort, either with new subject matter or material that was similar to mainstream output, but with a twist.
They found their programming in the cookery, antiques, gardening, house renovation and pet shows already on BBC and ITV, but moulded to fit their own particular viewers. For budgetary reasons, they had to forgo the star actors and presenters used by the main channels.
Then something unexpected occurred: the viewers themselves were already seeking their own 15 minutes of fame. At ease with the latest home-video cameras, they found themselves perfectly comfortable in front of TV cameras, too, whether being interviewed in the street about the latest political scandal or airing their dirty laundry in front of a national audience on Trisha or The Jeremy Kyle Show.
To show the people to the people, you no longer needed actors who could carry off an authentic Northern accent, because the people themselves were quite capable of turning up and performing their own variations of the Queen's English.
Cable and satellite television led the way, not by finding new formats, but by recombining old ones into fresh genres starring ordinary people in extraordinary settings.
In fact, the reality format has a long history. In 1948, the US producer Allen Funt, inspired by the success of his radio show Candid Microphone, had the brainwave of hiding a camera and setting up a scenario in which a member of the public or a personality was made to look stupid. Candid Camera was bought by commercial television in 1960 and its main stars were members of the public, who laughed themselves hoarse for seven years. Its format has been copied by Jeremy Beadle and Dom Joly among others, but people quickly became savvy in such matters. In the UK, they started filming their own pratfalls, mishaps and cute pets on video cameras and then mobile phones, sending them to You've Been Framed (1989-present) for cash prizes.
But perhaps the true beginning of reality television was the BBC "fly-on-the-wall" documentary The Family, which ran during 1974 and took cameras into the daily lives of the Wilkinses, a working-class family from Reading. We can no longer do fly-on-the-wall documentaries, except, perhaps, as postmodern irony, as the sitcom The Office (2001-03) proved. People are too cute to be caught out so easily. Instead, we watch our-selves watching ourselves, but this can produce memorable, spontaneous humour, too.
Take, for instance, ITV2's reality soap opera The Only Way Is Essex (2010), where the Jordan-wannabes Amy Childs and Sam Faiers were discussing Bonfire Night.
"What's Guy Fawkes all about?" asked the gormless, orange-skinned Amy.
"I dunno, it's old-fashioned," replied the amiable but vacant Sam.
All right, it's not Maggie Smith playing the acid-tongued Countess of Grantham (a very in-joke?) from ITV1's Downton Abbey, but it isn't far off. I really can't imagine the dowager holding a "vajazzle" party at the vicar's summer fete, which, by the way, Amy and Sam did, adding a wonderfully rich word to the dictionary ("vajazzle" is a combination of "vagina" and "bedazzled").
Today there is a deluge of reality television. We may treat ourselves to Channel 4's Three in a Bed - a dreary bed-and-breakfast competition, despite the racy title - or BBC One's Homes under the Hammer, a show dedicated to people buying the property of the evicted for bargain-basement prices at some saleroom or other. Or how about Channel 4's It's Me or the Dog (explanation of the premise in the title), BBC One's Cowboy Trap (a pun on rogue builders), Living's Passport Patrol (days in the life of New Zealand immigration officers) or Bravo's Brit Cops: Zero Tolerance, a gritty police docusoap suggestive of the Los Angeles ghetto but actually filmed in Hammersmith and Chelsea?
For those with a little more stamina, there's always BBC Two's Cooking in the Danger Zone, in which food writer Stefan Gates goes to disaster areas such as Haiti and Chernobyl and whips up a souffle for the locals. Of course, there's always the old standby, Living's Most Haunted, where a bunch of idiots run around in the dark in an old building for half an hour and see absolutely nothing while scaring themselves witless. OK, it's ridiculous, but at its height Most Haunted was hugely popular.
ITV and BBC fought back. The reinvention of Opportunity Knocks and Come Dancing reshaped and revitalised Saturday-night viewing. If the middle class and middle-aged should favour BBC One's Strictly Come Dancing, then there's still plenty left for the rest in The X Factor, hosted by evil pantomime villain Simon Cowell. Make no mistake, the best reality TV tells a story, and both these shows are constructed as narratives that include tropes from princesses (Cheryl Cole) to court jesters (this season, Wagner Fiuza-Carrilho and Ann Widdecombe), a curious mixture of Colosseum blood sport (with Cowell giving the thumbs up or thumbs down) and panto-style audience participation. Part of the fun is to boo and hiss.
My own vox pop analysis (comprising my son Jonathan and friend Yasmin) suggests that The X Factor is a "guilty pleasure". Yasmin watches Strictly not only because you see celebrities outside their comfort zones, but also because you see them growing in confidence and ability - or falling apart. The show's about "life-affirming values", she says, plus the excitement of seeing whether Pamela Stephenson will win or be pipped at the post by Matt Baker or Kara Tointon (who danced away with the glitter-ball trophy last weekend).
I doubt we have seen the last of Lord Sugar on The Apprentice or Strictly's Bruno Tonioli just yet, but reality TV is cheap and often nasty and the BBC has promised to clean up its act and produce quality broadcasting. This, no doubt, will inform as well as entertain and lay Lord Reith's ghost to rest before Most Haunted's Derek Acorah gets his psychic mitts on him.
BBC executives are following the example of ITV. ITV's Downton Abbey was the phenomenal success of this year's autumn season, winning 11 million viewers, and will be followed by the BBC remake of 1970s favourite Upstairs, Downstairs.
There's something unspoken going on here. The "golden" age of reality TV coincided with a buoyant economy, a certain swagger and a sense of confidence, but with the economic depression and much belt-tightening, we are retreating into the past for safety, eager for a nostalgic wallow in pre-First World War Edwardian splendour. Perhaps the ITV hit should have been called Downturn Abbey.