Mark Steel: There will be a Tesco store in your bedroom next

People are lured by cheapness, but pay for it by spending their time there in a vegetative trance

Tesco is terrifying. It's unstoppable, like bindweed. You couldn't even organise a guerrilla army against it because if you blew one up, two would spring up in its place. They must land in the night, like Triffids. Soon they'll have permission to set up Tesco mini-stores in your house, so you'll get up one morning and there it will be in your bedroom. And a PR spokesman will issue a statement: "Our customers have indicated that any lack of privacy that may result from having a shop by their wardrobe is compensated by the convenience of being able to purchase lasagne or shoe polish in the middle of the night without getting up."

But this Monopolies Commission report that's come out doesn't seem to care. It was set up specifically to comment on this rampaging monster and concluded it should be alright if it doesn't go much further. Who compiled that then - Neville Chamberlain? There's already hardly anything left they don't dominate. Next they'll take over drug-dealing, launching their new line with an advert in which Prunella Scales says to Jane Horrocks: "Don't expect me to do any housework tonight dear - not while Tesco are offering springtime savings on a quarter ounce of top quality Afghan skunk."

It's hard to identify what's so grotesque about these places, as they claim they're only so profitable because customers choose to go there. But a starting point has to be that no one in Tesco is ever happy. People are lured by cheapness and convenience, but then they pay for that by spending their time there in a vegetative trance, staring aimlessly into the despotic white light, maybe drifting back into consciousness for a moment to whack their kids on the back of their legs for climbing on the trolley, before the regular beep-beep of the bar code machine returns them to their hypnotic dreamy half-life.

Maintaining your faculties in a queue at Tesco is almost impossible. Once you're stuck behind six families with overflowing trolleys before it's your turn, you could be a multilingual biochemist and you'd struggle to remember the capital of France. These conditions should be used for training people who need to be able to think clearly in extreme circumstances, because if you can keep your thought process at 90 per cent in a Tesco queue, then repairing an oxygen mask while in space must be a piece of piss. And you even have to hire the trolley for a pound - the bastards. Even in Abu Ghraib they don't make you pay for use of the cattle prod.

And that's why it's wrong. Every boast they make is actually its crime. It is horribly irredeemably joylessly functional. Every tin of custard powder is placed at such an angle to entice you to chuck it in the trolley. Every tomato is perfectly spherically fluorescent. Occasionally they might decide that customers have indicated they appreciate conversational check-out staff, so the check-out staff will be ordered to say: "Hope you enjoy your evening." But that's worse than if they stared into space.

Tesco is the extreme end of modern town planning, in which every town is planned to look tortuously identical. You could be in Kettering or Greenland and you know that as you leave the centre of town, past Body Shop and River Island and Clinton Cards and some poor sod selling chocolate-covered almonds, down the road with the building societies and the Wetherspoons pub, just past the Esso garage and maybe a Big Yellow storage place, there it will be with its vast car park, symmetrical shrubs and slightly wrong clock.

Even the claim that shopping in Tesco saves time is mostly a con. People say: "At least I can get everything in one place." But the place is bigger than an average High Street. You might as well say: "I go shopping abroad because at least you can get everything in one place - France."

Or there's some "new" thing they're doing that's pointless, such as pre-packed diced pyramids of rhubarb, or bananas in balloons. "Now you don't have to pick your bananas off the shelf, just pluck them from the air as they float round in balloons that keep them extra-nana-fresh!"

All that driving and jostling can't make it much quicker or cheaper than going to a local shop, except the local shop's probably shut down because of Tesco. Then they boast they've set up a "green fund" when they're responsible for so many car journeys they'd be more green if they spent all day melting icebergs with a blowtorch.

And of course, because they're a massive multinational whose aim is profit, they screw people all over the world. So one report by Action Aid quotes a farm worker who picks fruit for a Tesco supplier in South Africa: "I sleep on the floor in a plastic sheet. There's no water or electricity and the walls of my shack are made of cardboard." For this she gets $18 a week. And they probably encourage them to buy the sheets from the local Tescos, who advertise: "Your sleep is complete on a sheet from Tescos."

But on and on they march. Soon they'll have their own team in the Olympics, then they'll develop a nuclear capacity and eventually rule everything. And we'd at least stand a chance if the next report says: "Look, the economics of it are a bit complicated to be honest. But what we do know is that Tescos is an abomination devoid of love or affection or humanity or imagination or even genuine animosity that could make a day interesting or unpredictable, just a corporate tyrant devouring us all with its soulless and chillingly inconvenient convenience."