The Scottish Government insisted its minimum-pricing plans would save lives yesterday after a watchdog warned the policy could backfire and increase sales of cheap alcohol.

The Office of Fair Trading (OFT) said the move would raise the profit retailers made from each bottle of low-cost alcohol, providing an incentive to sell more.

Ministers want every unit of alcohol to cost at least 50p, saying the move will save lives and cut incidents of alcohol-related harm.

A bottle of wine would cost at least £4.70 and a 70cl bottle of whisky no less than £14 under the scheme.

However, the OFT warned retailers would gain "additional profit for every unit of low cost alcohol they sell". The UK's consumer and competition authority said it was concerned that would give shops an "incentive to sell more rather than less low-cost alcohol".

It also warned a minimum price could set a dangerous precedent for politicians to intervene in the market.

The claims were made in evidence submitted by the OFT to the Commons Health Committee on David Cameron's plans to introduce a minimum price south of the Border. An OFT source said the concerns raised echoed those it had about the Scottish plans.

A Scottish Government spokesman said: "International evidence shows minimum pricing will reduce consumption and reduce alcohol-related harm.

"The Scottish Government already has a process to evaluate minimum pricing and this will consider the impact of our strategy on individuals, communities, the alcohol industry, and Scotland as a whole."