Smoked salmon rip off? Thin end of the wedge?

Sarah Coles
smoked salmon appetisers
smoked salmon appetisers

AP Photo/Damian Dovarganes

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?