THE supermarket giants would have you believe they are doing their public-spirited best for the embattled consumer.

Eight market leaders magnanimously have agreed a code to ensure that "special offers and price promotions are fair and meaningful".

Not before time, you might think, since almost three-quarters of consumers believe supermarkets are trying to mislead them.

So does this mean Tesco, Sainsbury's, M&S, Morrisons, Waitrose, Aldi, the Co-op and Lidl admit their special offers have been unfair and meaningless? You wish.

Neither have they suddenly embraced altruism under their own steam.

They were prodded into this unholy chain reaction by the Office Of Fair Trading, which itself was roused by a year-long Which? investigation into "misleading" pricing tactics.

Asda has yet to sign up.

The UK's second biggest chain, owned by American giant Walmart, is probably too busy firefighting claims of tax dodging.

Supermarkets pay big bucks on marketing and public relations to appear caring and customer-friendly.

But you have all encountered one of their stings, or perhaps you didn't realise.

I don't mean the daftest deal found by Which? – packets of sweets at 34p each or four for £3! If you fall for that you are beyond help.

No, big bucks buys more subtle marketing. The Godfather could not improve on supermarket offers folk can't refuse.

l An item's shelf price is doubled when promoted as a money-saving multi-buy, then decreased again when the promotion ends. This is called "yo-yo pricing" (or stringing the customer along).

l Store A charges one price, Store B charges a lower price and announces "was £x, now £y", when the higher price was never charged in Store B.

l Advertising a price reduction, but failing to mention it is only because the contents have shrunk.

l The old favourite, Buy One, Get One Free, where the same volume of the same product is cheaper in a larger pack.

Misleading advertising is illegal under the 2008 Unfair Trading Regulations, yet the OFT, unlike Which?, says its latest investigation did not find any. Just "inconsistency" in how the law was interpreted.

Its new code will ensure promotions reflect "the spirit as well as the letter of the law". Good luck with that at Christmas.

Shoppers should not need calculators to ensure they are not being duped, but that is what it is coming to.

Fairer price labelling would help. Instead of the unit price being hidden in the small print on the shelf-front, it should be on the product.

And how about scanners shoppers can use to reveal the real cost-per-unit, whether the item is in both grams and mls and whatever its size.

We are told to keep a running total of our purchases, but how many shoppers check their receipt against the shelf prices?

How many remember the shelf prices when they get through the check-out?

How many arrive home bursting for a nice glass of wine?

There's an offer you can't refuse. Every little helps.

nSTARBUCKS is talking to HMRC about joining the rest of us UK taxpayers.

Despite UK sales of £400m last year the coffee firm paid no corporation tax. Not a penny.

Starbucks said it had listened to customers and "to maintain public trust we need to do more".

If that is not a tax dodging, boycott-fearing confession, then I'm a Tory. Still, better latte than never.

So much for scaremongering fat cats saying we will chase big firms away from Britain. Turn their backs on £400m? Gie's peace.

Now for Google, Amazon, Vodafone, Boots, TopShop, Facebook ...