The legislation to bring in a minimum of 50p a unit was passed by Scottish MPs in May 2012. A legal challenge was brought by the Scotch Whisky Association (SWA).
The European court ruling said: “The Court of Justice considers that the effect of the Scottish legislation is significantly to restrict the market, and this might be avoided by the introduction of a tax measure designed to increase the price of alcohol instead of a measure imposing a minimum price per unit of alcohol.
“The court states that it is ultimately for the national court to determine whether measures other than that provided for by the Scottish legislation, such as increased taxation on alcoholic drinks, are capable of protecting human life and health as effectively as the current legislation, while being less restrictive of trade in those products within the EU," the ruling stated.
SWA chief executive, David Frost said: “We welcome the European Court’s ruling. The SWA always said European Union law issues were central to this case, and so it has proved. This settles EU law issues once and for all.
“The court has confirmed that minimum unit pricing (MUP) is a restriction on trade, and that it is illegal to choose MUP where there are less restrictive ways of achieving the same end.
“The Scottish courts will now reflect on the implications of the ruling and all the evidence, before issuing a final judgment," he said.
“This ruling opens the way to moving the debate on and allowing us to address alcohol misuse with practical measures that actually work. Alcohol-related deaths have fallen by a third over the last decade in Scotland, which suggests we are already on the right path. We remain committed to working closely with the Scottish Government and everyone else with an interest,” concluded Frost.
The ruling of the Luxembourg court will be referred back to the Court of Session for a final decision. Whatever the Court of Session decides could then be appealed to the UK Supreme Court in London.
Under the proposal, the cheapest bottle of wine (9.4 units of alcohol) would be £4.69 and a four-pack of 500ml cans of 4% lager would cost at least £4. It would mean a 70cl bottle of whisky could not be sold for less than £14.
The legal bid by the SWA was backed by other European wine and spirits producers. It was initially rejected by judge Lord Doherty at the Court of Session in Edinburgh in 2013. Following an appeal hearing, the case was then referred to the European court.