MPs for Scotland's ruling national party have found themselves isolated in the country's Parliament, over plans to raise the legal age for buying alcohol in shops to 21.

Opposition MPs from all main parties rubbished the proposal during a heated debate in Parliament this morning (2 October). A vote this evening was widely expected to inflict defeat on the government.

Although not binding, opponents within the drink industry and beyond say a victory would send a strong message to the ruling Scottish National Party.

Around 100 protestors gathered outside Parliament this morning, in a rally organised by the student-led Coalition Against Raising the Drinking Age in Scotland (Cardas).

Tom French, Cardas co-ordinator, told just-drinks: "Everyone is united about the need to tackle alcohol abuse, but everyone is united against this proposal."       

Scottish justice minister Kenny MacAskill, who has spearheaded the plan to raise the off-trade buying age, was not present for this morning's debate.

The proposal is part of the SNP's draft alcohol strategy for Scotland, which also includes provision for minimum pricing and restrictions on promotions. Ministers say alcohol-related harm costs the country GBP2bn (US$3.5bn) annually.