A legal challenge against minimum pricing for alcohol in Scotland has been referred to a European court.
Judges at the Court of Session in Edinburgh have ruled that the case against the Scottish Government's policy should be referred to the Court of Justice of the European Union (EU).
The legal challenge was brought by the Scotch Whisky Association, which has argued that minimum pricing legislation breaches European law.
Health Secretary Alex Neil welcomed the referral from the court and stressed that it was right this "precedent-setting case" was considered by the highest authority on EU law.
The Scottish Government says minimum pricing is needed to tackle Scotland's problems with alcohol misuse.
Mr Neil said: "Scotland has a difficult relationship with alcohol and we need to urgently take action to tackle this problem that puts a huge burden on our society.
"The evidence shows that minimum unit pricing is an effective way to tackle alcohol-related harm. This is because it targets heavy drinkers in particular as they tend to drink the cheap, high-strength alcohol that will be most affected by the policy.
"While it is regrettable that this means we will not be able to implement minimum unit pricing sooner, we will continue our ongoing and productive dialogue with EU officials."
Scotch Whisky Association (SWA) chief executive David Frost said: "We are pleased that the Court of Session in Edinburgh is referring the minimum unit pricing (MUP) case to the Court of Justice of the European Union. From the outset we said that we believed MUP was contrary to European Union law and that it was likely in the end to go to the European Court.
"We also believe MUP would be ineffective in tackling alcohol misuse and would damage the Scotch whisky industry in the UK and overseas."
The Alcohol (Minimum Pricing) (Scotland) Act 2012 was passed by Holyrood in June 2012, paving the way for the introduction of a preferred minimum price of 50p per unit, but its implementation has been delayed by legal challenges.
The SWA's legal bid was rejected by Lord Doherty in May 2013 following an Outer House hearing in the Court of Session in January 2013.
An appeal to the court's Inner House, heard by Lord Eassie, Lord Menzies and Lord Brodie, took place in February.
The appeal hearing focused on what the aim of minimum unit pricing is, whether this aim could be achieved using alcohol excise duties which would be less distortive to the free movement of goods (Article 34 of the Treaty on the Functioning of the EU (TFEU)) and whether the policy was proportionate to protect public health and therefore justifiable under Article 36 of TFEU.
In a written opinion published today, Lord Eassie wrote that "the present proceedings raise aspects of those tests and of the role of the national court which are not clearly established".
He continued: "There are thus aspects to the Scottish Ministers claim of justification under Article 36 TFEU upon which we consider that it would be of help to have the guidance of the Court of Justice of the European Union."
Dr Evelyn Gillan, chief executive of Alcohol Focus Scotland, said: "If the appeal judges feel that clarification is needed on technical matters then we can only hope that this process does not drag on.
"Every week that minimum pricing is delayed, another 20 Scots lose their lives because of alcohol.
"It is frustrating to see a policy that has been agreed through the democratic process being held up by big business, who care more about protecting profits than the health and well-being of the people of Scotland."