Last week, on the way to Waitrose, I popped next door and bought a television. Although the only things on my list were lemons, lightbulbs and dog food, the television purchase was the result of careful financial planning. When televisions skinnier than a novel by Ian McEwan first appeared, they cost less than a term at boarding school, but more than a used Ford Fiesta. I figured that in a couple of years prices would plummet, so I decided to rent one and wait. It’s amazing what you can rent these days: washing machines, irons, microwaves, dishwashers. And the men who deliver and install rental televisions are as friendly as Jehovah’s Witnesses, cheerfully returning for free whenever there’s a problem.

I was right about the prices dropping in just two years prices have halved but what I didn’t figure into my calculation was the size of the showroom versus the size of the room where the new television would reside. In the olden days of Upstairs, Downstairs, this was the staff sitting room. By the time I arrived here, the staff had dwindled down to two, who lived in the village, and the room became what used to be called a den, spiritual home of the family television. However, the 40in Sony Bravia digital HD-ready television that required two men to lift it out of its box looked more like the scoreboard for a cricket match at Lord’s.

‘Everybody thinks that at first. You’ll get used to it,’ explained Kevin as he tuned the set. ‘Don’t worry. We’ll leave the box. You have 28 days to change your mind.’ Blessed is the consumer who is treated kindly, which is why consuming is so much more satisfying that paying taxes. And Kevin was right. Within 15 minutes, the discreet matte black television looked as beautiful to me as the Tudor fireplace.

‘It’s rather intrusive, don’t you think?’ asked my husband when he came home. “Wow,’ said the teenagers, before occupying the sofas like beached tuna. And so the days passed which were given to us, now mesmerised by the rolling fairways of Augusta, Georgia, the leafy yards of Wisteria Lane and the DVD mountain that’s come free with newspapers. The only thing missing was room service.

In fact, the television moved into our lives as quietly as a stealth tax. Until, that is, we settled down to watch Big Ideas that Changed the World. We were still in festive mood as the camera scanned one of the country’s 12,000 landfill sites, bulging with the 100 million tons of waste we throw away each year. The camera zoomed in on a moonscape of fridges, a crater of dead televisions all the more vivid on a screen as flat as a Kansas prairie. The evangelical Jonathon Porritt warned us: ‘Fascism. Communism. Democracy. Religion. But only one has achieved total supremacy… more powerful than any cause or even religion, it has reached into every corner of the globe. It is consumerism.’

According to Mr Porritt, Britons throw away their own body weight in rubbish every seven weeks. Computers and televisions tossed into landfills destroy the drinking water for miles around. Our present levels of consumption are killing the life-support systems on which we depend. Our only hope? We’ve got to stop shopping. I know Mr Porritt’s right when he says that we will have more elegant, satisfying lives if we consume less, although I confess I’m glad I bought my slender television to console me in my conversion. Did I say it was matte black, elegant and satisfying?