* Asda - I went there a few days ago (4th August), and they had signs up at every till saying that they would no longer give out carrier bags after 1st August; instead, people can buy a "Bag for life" (heavy duty plastic). Since I reuse my normal bags, I've never bothered to buy the stronger ones, but this idea has potential. It was slightly undercut by the fact that all the tills were still giving out the normal bags to customers, but I'm hoping that they just want to use up their existing stock.
* Sainsbury's - they started a new policy recently, where you earn 1 Nectar point for each bag that you reuse. This is the carrot rather than the stick, and it is slightly open to abuse (e.g. if I decide to double wrap everything even when I don't need to), but if it gets people into the habit of carrying empty bags with them then it's worthwhile.
* Tesco, Somerfield - at my local stores, the tills are a bit like a post office counter, i.e. you approach and then go back the way you came, rather than walking through to the other side. That means that there's a much smaller space available for bagging; it's ok if the staff fill new bags for you, since they can swipe items and put them straight into the bag, but it's much harder to reuse my own bags because I have to take the items off the counter and fill the bag that I'm holding in the air. That's a bit cumbersome, and because I'm working one handed I can't really keep up with them. Ideally, I could just give my empty bags to the cashier, but none of their staff seem to be particularly enthusiastic. In fairness, they may have more space available in other branches, but they certainly don't seem to have any company-wide policy about reducing the number of bags they use.
Ah well, I'll keep trying to do my bit, and I'm more likely to shop at the stores that make it easier for me.