There is a hell of a lot of bluster around this potential policy.
Someone, not sure of their political persuasion said that the problem is largely cultural. I agree.
That leaves the question of how you change culture.
WARNING: This is the bit where I go off-piste and probably offend people. My intention is not so, it is merely to get right to the nub of the problem.
Education? Nope. That's telling people what they should be doing. That is seen as them Vs us, "who are they to tell me what to drink and when?" It will, and is, ignored not just by the tramp juice swilling masses, but by the middle and upper classes too.
Legislation? More likely to succeed. But it's expensive and difficult and the results will take a long time to come, as people come to understand that they will end up with a record just for being too p***ed gradually society will become averse to that risk. Yes you'll lock a few people up in the short term but it takes a massive and sustained pressure to change culture for the long term. That's really expensive, we can't afford it.
Taxation? (or other forms of monetary manipulation) Again, more likely to succeed than education. The concept is that you make it more financially difficult for the target groups - and this really does appear to be targetted at the young, not affluent, "drink just to get p***ed" group - to take the actions you are trying to curb. Minimum pricing does, on the face of it, exactly that. The problem, we're led to believe, is that people are getting most of the way there at home on tramp juice then going to the pub and finishing the job with a couple of pints of f***ers or wife beater, thowing up on the barmaid and picking a fight with the taxi driver. If the hunch is right then these people have a finite cash reserve to get wasted on. If the price of tramp juice doubles to £4 for two litres then pre-loading becomes expensive too and hopefully you bring people under the "I'm wasted" threshold. Once you've done that, you have less people doing it, therefore less people thinking it's cool and maybe just maybe with education and legistlation to back it up you stand a chance of pushing people towards responsible drinking...
...and by that I mean understanding and taking an interest in drink, the production, the craft, what's good, what's bad, what's ugly. Let's face it, if you can't get smashed for a tenner, and tramp juice is not far off the price of good drink then a proportion of the affected will spend their tenner on slightly less, better drink and appreciate drinking the way drinking is supposed to be appreciated. So when you add the legislation and enforcement on top and back it up with education (not preaching about the evils of drink but education around good drink, craft production and the positives of "good" social drinking) then you have the package that can make the difference.
Will it work? Probably not, because the minimum price will be set too low due to pressure from the s**te drink manufacturers and other lobbying groups and the whole thing will get watered down, cash won't be available to toughen up on the "pre-loaders" and the drinks industry as a whole will oppose it all and not provide the right educational angle as all they're interested in is bulk volume, commoditised alcohol sales.
Shame really, done right it could make a real difference.