"Have you got your points card?" they ask at the checkout as they invite you to rifle through your wallet crammed with such things and check your key fobs while you try to pack stuff into the plastic bag you've just bought because as an anti-social dullard you forgot to carry one about your person at all times.

But at least the supermarkets get the concept of loyalty. Jeezo, I can even remember my mother's Leith Provident Co-op number which I had to quote when sent with half a crown to buy a forpet o' tatties. Later it was stamps, at one time of the Green Shield variety, which rewarded loyalty.

The point is, supermarkets have always recognised how easy it is for you to switch to a rival; indeed Aldi and Lidl are proving it today as they strike terror into Tesco and Safeway. You just go into the shop next door or drive into a different car park. OK, you might have to recognise the new layout of the aisles, but it's no big deal.

So why is it that that Adam Smith's invisible hand turns into a withered stump when it comes to so many suppliers of the other necessities of life such as financial services and public utilities? What is it about these which defy the supposed economic laws of supply, demand and competition?

The focus today is on the energy suppliers who stand accused of promoting what can only be described as loyalty penalties, their policy being: "Stick with us and we'll rip you off."

This is no exaggeration, as a competition inquiry suggested that 95% of us who take our energy supplies from a single sources could have saved up to £234 by switching supplier.

But don't worry, if you have a bank account or a credit card, or buy extra television channels, or telephone or broadband, or home or car insurance, you're probably paying loyalty penalties too. All these various service providers are concentrating their energies on potential switchers, and by extension, screwing existing customers.

Part of this is the fault of the feeble nature of our Competition and Markets Authority, authors of yesterday's report into the Big Six energy companies, and about as toothless a watchdog as ever failed to strike fear anywhere, although we can rest assured that Energy Secretary Ed Davey "would not flinch" from tough action.

The report said Centrica, SSE, npower, EDF, Scottish Power and E.ON appeared to be punishing those on standard tariffs - "the less well-educated, less well-off, struggling financially, less likely to own their own home and have internet access and more likely to be disabled or a single parent".

Damning stuff. But the better off get gulled too, punished for the sin of working long hours and not wanting to spend their increasingly squeezed leisure time puzzling over tariffs and suppliers and endlessly logging into websites to try to do something about it.

A good friend of mine loves all this stuff. He also likes to haggle at markets when on holiday and will drive the length of Britain to nail a good deal on a new car. In other words, it's his hobby. A hobby is meant to be voluntary, not a vital way of avoiding being ripped off by loyalty penalties. Change, as we did recently with a bank account, can be relatively smooth, but you are just as likely to miss a deal by constantly jumping ship as you are to seal one.

All of this has flowed from the days of "Tell Sid" and the sell-off of British Gas. Not only was it meant to create a share-owning democracy, it was meant to introduce a golden era of competition into the energy sector and then all other public services to the benefit of us all.

The results have been mixed, most notably in rail services where few would now argue that the break-up of British Rail was a success. East Coast having to be taken back into public ownership was the best example of that, and pricing and ticketing structures in the fragmented system remains notorious.

It is certainly the case that some of the old state monopolies in power and telecomms were sluggish, unresponsive and poor at customer service.

The trouble is that their successors all too often appear to act in concert in a monopolistic way and use their new commercial freedoms and nimbleness of response not to serve customers but to stiff them, to penalise rather than reward customer loyalty.