Who provides TESCO'S with these bags. cheers.

Oh please don't involve SEO - Tesco needs suppliers that can deliver volume, not words!
Also, the whole premise of plastic bags needs discussion - for it is my understanding that the environmental issue is far from clear-cut.
The original complaint from the green-lobby was that the bags damaged wildlife - well we only care to some extent, as six-pack packaging is still made - it has been linked to deaths of hedgehogs, who get caught in the can-rings. (Perhaps if it was robbins that would be a different story?).
However, it appears that most wildlife isn't "that stupid" to attempt to eat plastic bags - although it is recognised many animals swallow stones to aid digestion process.
One issue leveled at bags is that they last hundreds of years and contaminate landfill - this I don't believe, Firstly landfill is a sealed environmnet, to avoid liquids finding their way into water-courses, furthermore the atmosphere is monitored so no nasty-niffs. Finally, the bags I have arround the home and garden rarely last more that 3, or four years ( less outdoor, including larger heavy-duty bags from builders).
So where is the problem with supermarket bags? Personally I like them, they are useful for wrapping things and so on. I prefer the clear-variety, so much easier to check what's inside.....but they have a limited life, so need replacing.
If supermarkets charge for bags and folks wish to re-use them, then they will have to be stronger and last longer. So whilst the "number" of bags might drop ( less than half?), they will last longer, which kinda-negate the whole process.
Yes, I know they are supposed to be bio-degradable, but folk won't choose to pay for these.....with a short-life.
No I don't think I get it at all, esp. as the original premis is far from proven.
-Incidently checkout-bags were introduced to prevent pilfering and to advertise the store.