I think the chances of any government taking on Tesco and Asda are pretty slim. But I agree. The idea of minimum alcohol pricing is essentially a good one, but it could be improved by differentiating between on and off license sales.
My thoughts would be to impose a high minimum per unit price in the off-trade and bring in limits on the number of off-licenses. I'd then impose a much lower rate of duty and lower minimum price for the on-trade. This would encourage people to drink in pubs, bars and clubs, not at home. The social and economic benefits of that should be self evident.
My basic idea is that, as a general rule, it should never be cheaper to buy alcohol in a shop than in a pub.
The other thing I'd do is to toughen up the legal powers to deal with landlords who allow excessive drunkenness on their premises.
You are aware that the proposed minimum pricing will not alter the price of drinks in a pub?