Jinx1906, I use the free plastic bags supplied by Tesco as do millions of other citizens. We don't all believe the dodgy dossiers and the planners' pronouncements. Most people ignore the spin and hype. They are not as daft as the planners think.
Supermarkets are competitive, they shave pennies off their products in order to entice more people into their stores. Supermarkets that offer free strong plastic bags will attract more customers than those who don't. I wouldn't shop at a supermarket which charged me for plastic bags, and nor would many other people.
Supermarkets want to make their customers happy, they train their staff to provide good service and they offer you help with packing your bags. They would not shoot themselves in teh foot by trying to make profit from plastic bags. The plastic bag thing is not about saving money, it's about "hearts and minds". The planners are educating teh public for their future policy pronouncements about rationing.
They are cutting back the welfare state, they are increasing pensionable age, they are saying "you can't have something for nothing", even though people have paid taxes all their lives. They are talking about the "deserving" poor, and they haven't yet mentioned the "underserving" poor (but don't worry they haven't forgotten them). They are training the public to accept austerity, to swallow massive reductions in living standards and benefits that they have been paying for. They are readying the public for the "carbon footprint" tax and "saving the planet" and plastic bags are a small part of the education process.