HEALTH Secretary Nicola Sturgeon is expected to reveal today she is setting the minimum price for a unit of alcohol at 50p.

The move, which is backed by the medical profession and police, is aimed at tackling Scotland's serious alchohol problem.

However, retailers are opposed to the policy and legal challenges are expected from some drinks manufacturers.

Ms Sturgeon has said she was introducing the policy "to stem the flow of cheap high-strength drink".

The legislation, backed by the Tories and the LibDems, will be passed by the Scottish Parliament next week and make Scotland the most expensive country in the UK to buy alcohol.

The industry definition is that 10 millilitres of pure alcohol equals one unit and a 50p per unit price means at 75cl bottle of wine containing 10.1 units will rise from £3.33 to £5.05.

Other research predicts the hike will increase the price of a £10.50 bottle of vodka to £13.13, whisky currently priced at £17 will go up to £20 and a multi-pack of lager selling at present for £12 will increase to £16.72.

Ms Sturgeon, who will make the announcement during a visit to a gastroenterology ward at Glasgow Royal Infirmary, has admitted minimum pricing is not a "magic bullet" for solving the problem, but told MSPs it was "essential if we are to make a significant contribution to reducing consumption".

She said: "My point is this – no strategy will be complete with addressing price. The link between price and consumption and between consumption and harm is irrefutable."

The 50p level is 5p higher than Ms Sturgeon has previously used an illustrative price and takes into account inflation and duty rises.

A Scottish Retail Consortium spokeswoman said: "Price is a very blunt instrument which will affect the vast majority of people who are responsible drinkers while doing little to help those with a real problem."

She said tackling the problem depended on a wide range of responses, including education.

Gavin Hewitt, chief executive of the Scotch Whisky Association, said the measure would be ineffective, claiming the Government's own research showed it would not reduce the number of hazardous drinkers and that it has "consistently been ruled to be illegal in Europe".

He added: "The introduction of minimum pricing in Scotland will damage the Scotch Whisky industry in overseas markets by setting a precedent that third countries will use to justify 'health related' protectionist measures against Scotch overseas at a time when the Government is trying to encourage an export led economic recovery."

Labour, the only Holyrood party to oppose the measure, insisted it was the wrong way to tackle the problem because it would mean a £140 million a year boost for big retailers.