Minimum pricing, or bans on selling below cost price, will be difficult to enforce, they are illiberal and they will, through the basic actions of economics, impact on the price of all substitute goods and all substitutes or substitute etc. (especially where those substitute goods are sold by the same vendors).
To define "cost price" is also going to be difficult.
You don't have to be William Gladstone to understand that a government enforced cartel in the drinks industry is a very bad idea. It can only benefit the drinks industry, at the expense of consumers.