Researchers at Which? discovered an astonishing phenomenon in the fancy smoked salmon section of the supermarket. In a recent test, 25 out of 32 packets of smoked salmon weighed less than the price printed on the label.
So what's going on, and can this be fair?
Which? weighed 32 packs from Asda, Morrisons, Sainsbury's and Tesco, and found that 25 weighed less than the labels said - and seven weighed more. On average, the light packets had 2.4% less than the label stated.
In fact, the rules give supermarkets and manufacturers a bit of leeway between the weight in the packet and the one listed on the label - which they call tolerable negative error. They are allowed to be 9% out and still fit within the rules.
You can understand this to a certain extent: a fish is a certain size, and nature doesn't conform to a one-size-fits-all approach. We can't expect supermarkets to go around chopping products and wasting huge chunks of fish in order to ensure the weight exactly matches the listing on the packet.
All but one packet fell within the rules laid down by Trading Standards on how far out the weights were allowed to be. The one exception was a single pack of Tesco Everyday Value Smoked Salmon, which was listed as 200g, but actually contained 181.5g. Tesco explained this was because some of the oil transferred to the packet while it was on the shelf. It said the packet itself would have conformed to the rules when it was packed.
Which? itself said the results should be treated with some caution as it wasn't a full in-depth piece of research.
Does this worry you?
So, given that they stay within the rules, should we be bothered by this piece of research at all?
On the one hand, they are within the rules, they are making understandable decisions, and you can see what is in the packet when you buy it - so if something looks a bit small you can put it back and get something else.
However, on the other hand, it's interesting to see that so many over-estimated the weight of the food. In many instances, therefore, it would seem to indicate that when it's hard to be bang-on the weight, the supermarkets tend to err on the side which happens to be most profitable.
A Tesco spokesman refused to be drawn on this subject, insisting that they always conformed to all the Trading Standards Rules.
Clearly Which? only tested 32 pieces of smoked salmon, so it would be wrong to infer that this was the case across the supermarket. However, fresh produce conforms to similar rules. Smaller packets have to be within 9% of the weight on the packet, and larger packets within 1.5%-4.5% depending on the quantity or weight. This seems logical. After-all when weighing out fruit and vegetables, they're not going to start chopping tomatoes and grapes in half to ensure a dead-on accurate weight.
Clearly they are regularly making decisions on whether to go over or under. There is no indication as to whether they tend to err on the side of generosity or on profit
However, it raises the question of whether we would be better off weighing our own fresh produce, or getting things like smoked salmon at the deli, so you are getting exactly what you pay for.
But what do you think? Let us know in the comments.
10 of the biggest consumer rip-offs
Smoked salmon rip off? Thin end of the wedge?
Using a mobile phone to make and receive calls, send texts and browse the web while abroad can be extremely costly – especially if you are travelling outside the European Union (EU), where calls can cost up to 10 times as much as at home.
To avoid high charges, Carphone Warehouse suggests tourists ensure a data cap is in place, use applications to check data usage, turn off 'data roaming', avoid data-intensive applications such as Google Maps and YouTube and use wi-fi spots to update social networking sites.
Payment Protection Insurance (PPI) is supposed to help people to continue meeting their loan, mortgage or credit card repayments if they fall ill or lose their jobs. However, policies are often over-priced, riddled with exclusions and sold to people who could not make a claim if they needed to.
At one point, sale of this cover - which was often included automatically in loan repayments - was estimated to boost the banks' profits by up to £5 billion a year.
Now, though, consumers who were mis-sold PPI can fight back by complaining to the bank or lender concerned and taking their case to the Financial Ombudsman Service (08000 234567) should the response prove unsatisfactory.
It could be you, but let's face it, it probably won't be. In fact, buying a ticket for the Lotto only gives you a 1 in 13.9 million chance of winning the jackpot.
With odds like that, you would almost certainly be better off hanging on to your cash and saving it in a high-interest account.
No-frills airlines such as EasyJet may promote rock-bottom prices on their websites. But the overall fare you pay can be surprisingly high once extras such as luggage and credit card payment fees have been added - a process known as drip pricing.
Taking one piece of hold baggage on a return EasyJet flight, for example, adds close to £20 to the cost of your flight, while paying by credit card increases the price by a further £10.
It may therefore be worth comparing the total cost with that of a flight with a standard airline such as British Airways.
Cash advances, which include cash withdrawals, are generally charged at a much higher rate of interest than standard purchases.
While the average credit card interest rate is around 17%, a typical cash withdrawal of £500, for example, is charged at more than 26%.
What's more, as the interest accrues from the date of the transaction, rather than the next payment date, costs will mount up even if you clear your balance in full with your next payment.
Supermarkets such as Tesco and Asda often run promotions under which you can, for example, get three products for the price of two.
However, it is only worth taking advantage of these deals if you will actually use the products. Otherwise, you are simply buying for the sake of it, which is a waste of your hard-earned cash.
Buy a train ticket at the station on the day of travel and the price is likely to give you a shock - especially if you are travelling a long distance at a busy time of day.
However, you can cut the cost of train travel by 50% or more by going online and making the purchase beforehand - especially if you book 12 weeks in advance, which is when the cheapest tickets are on sale.
Other ways to reduce the price you pay include avoiding peak times and taking advantage of so-called carnet tickets, which allow you to buy, for example, 12 journeys for the price of 10.
Most High Street banks offer packaged accounts that come with monthly fees ranging from £6.50 up to as much as £40, with a typical account charging about £15 per month.
Various benefits, such as travel insurance and mobile phone insurance, are offered in return for this fee. But whether or not it is worth paying for them depends on your individual circumstances.