I doubt they will make a profit out of it. The increase in the tax take is not going to be enormous. Given that most alcohol prices won't be affected, it is not going to raise huge amounts of money. The actual cost of enacting and enforcing the measures - plus the increase in smuggling of the goods most affected by the price rise could well end up costing money.
I understand where you're coming from but I have to disagree. What does it cost to pass a law that states supermarkets have to charge a minimum price per unit? In the great scheme of law creation I doubt the overall cost is significant.
Let me go back to the bog-standard Tesco lager. 4x440ml cans, 2% alcohol, costing £1.00. I'm no mathematician, but I'm figuring that's 8.8ml of alcohol per can. One UK unit of alcohol is 10mls. So those cans contain roughly 3½ units.
So, if you're going to charge a minimum of 45p a unit then you're talking about a revised cost of £1.58 for that four pack. Bear in mind that the previous price of £1.00
included VAT, whereas this new price is just the
base alcoholic unit price. So, VAT @ 20% = 32p.
Booze that previously cost £1.00 increases to £1.90 - that's nearly
doubling the price - and that's just some bog standard piss-ale that you'd have to have a skip-load full to even get tipsy on. Try the math on a bottle of Kopperberg - 4.5% volume and already about £2.18 a bottle (the minimum price of the alcohol in one bottle would be £1.17 - that's before VAT, whatever the supermarket lobs on to make a profit etc).
And, once you take into account that the minimum unit price will not
stay at 45p, but will continue to rise, then you can see it's only a matter of time before this becomes a nice little earner for the government. Perhaps not now, but as soon as they realise it's not having the health impact they want, they'll just use it as an option to rake in more cash.