SNP ministers at Holyrood appear determined to press ahead with their widely criticised plan to ban under-21s in Scotland from buying alcohol in off-licences and supermarkets despite a crushing parliamentary defeat on the proposal last night.

Labour, Liberal Democrat and Conservative MSPs joined forces to back a Tory motion calling on the Scottish government to scrap the plan.

Although the vote, in which the ban was defeated by 72 votes to 47, is not binding on ministers because it was not on a piece of legislation, it now appears highly unlikely that it can ever become a reality.

Nationalist sources indicated that the proposed ban would still be included in the forthcoming Justice and Licensing Bill. “Ministers are very confident of the merits of the measure,” a senior government source said.

One explanation at Holyrood for the SNP's bullishness is that they feel that the proposal has widespread public support and that too much emphasis has been laid by the other parties on the opposition of students and retailers who would be directly affected.

They feel that with many areas of Scotland falling victim to the social and criminal results of teenage drunkenness, political opponents will be blamed for the failure to take action.

Opponents have pointed out that the ban would mean that under-21s would be able to manage an off- licence but be unable to buy a bottle of wine there. They also argue that a soldier aged 20 on leave from Afghanistan would not be able to buy beer from an off-licence. Others have pointed out that it appears inconsistent that under 21s would be able to drink as much as they wanted in a pub but would break the law if they tried to buy a bottle of wine in a supermarket.

Kenny MacAskill, the SNP Justice Secretary, defended the proposal, insisting that Scotland's “booze culture”, estimated to cost the country's economy £2.25billion a year, was so great that action was needed.

Mr MacAskill pointed to three pilot projects for the ban that were implemented in towns in Central Scotland and which resulted in a 40 per cent drop in drink-related offences, vandalism and breach of the peace.

He said that 40,000 people a year had to be treated in hospital for an alcohol-related illness, adding that Scotland had one of the fastest-growing rates of drink-related liver disease and cirrhosis in the world.

He claimed alcohol abuse affected everyone in Scotland, saying: “We do need legislative change, because the status quo is unacceptable.

“The difference between us and the other parties is we recognise the scale of the problem and are willing to try new approaches to tackle it.”

The Tory motion was put forward by Murdo Fraser, the party's deputy leader, who denounced the plan as “ludicrous”, and said that there was the “huge backlash” to the idea from retail and student bodies, including the Federation of Student Nationalists.

He added: “We believe that it is wrong in principle.”

“We have problem drinkers at every age in society. To target the 18 to 21-year-olds suggests that that group alone has a specific problem. The proposal is discriminatory and there is simply no evidence to back it up.”

The existing laws, he said, needed to be better enforced because only seven people were taken to court in 2005-06 for buying alcohol or drinking it in a bar when they were under 18.The issue also dominated First Minister's Questions later, with Iain Gray, the Labour leader, challenging Alex Salmond to “dump this daft plan”.

Mr Salmond, in turn, attacked Labour, Conservatives and Liberal Democrats for not responding to the government's consultation on a package of anti-alcohol measures. He claimed that the previous Labour-Lib Dem coalition had failed to confront the issue. “We are finally seeing proposals to face down Scotland's relationship with the booze,” he said.

“Shouldn't it be welcomed by this whole Parliament?”

Annabel Goldie, the Tory leader, dismissed Mr Salmond's “attempt to defend his proposed criminalisation of responsible young adults”, as the “most bizarre that this chamber has ever listened to”.

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