We use plastic shopping bags as bin liners, among other things. We even have a nice linen dispenser for them so newly acquired bags squish in the top and we pull them out of the bottom when needed.
But it seems that we will have to start buying plastic bin liners instead of using the shopping bags even though ...
Plastic bag campaign falls apart at the seams | The Register
... And the bin liners are not as good as the shopping bags because they don't have the handles we use to hang the nominated trash bag on the kitchen cupboard door.
As Private Eye might say - it's trebles all round for the bin liner manufacturers and the stores that will now sell lots more of them.