MSPs have backed plans for a law change to reduce the drink-drive limit, as a new survey found seven out of ten Scots supported the move.

Calls to cut the limit from 80mg of alcohol per 100ml of blood to 50mg were backed overwhelmingly in a Holyrood vote.

It followed an Ipsos MORI poll showing seven out of 10 Scots agreed, with 55% "strongly" supporting the plan. Just over one-quarter (26%) opposed a cut in the limit.

Support for a reduction was strongest among those aged 55 or over, with 73% of the age group backing a lower limit. Three-quarters of people living in rural parts of Scotland also favoured tougher laws.

The poll of more than 1000 people came as MSPs debated calls to reduce the drink-drive limit for the first time since powers were transferred from Westminster.

The Scottish Government has launched a consultation on the issue and is expected to legislate in the coming months.

Justice Secretary Kenny MacAskill told MSPs that one in 30 drivers involved in accidents last year were over the limit or refused to take a breath test.

Drink-driving led to 750 casualties in 2010, he said, though the figure has fallen from 1150 in 2000.

He added: "While we welcome a reduction in the number of casualties, I still find these figures unacceptably high.

"The people of Scotland are fed up with drink-drivers and their poor excuses. It is both remarkable and tragic that a significant minority of drivers still ignore the warnings.

"We believe the current limit has had its day.

"The time is right for a change that will bring Scotland in line with the vast majority of Europe. If you look at the drink-driving limits across Europe, it is only the UK and Malta that have a legal blood alcohol concentration limit of 80mg of alcohol per 100ml of blood."

Holyrood was handed control over drink-drive limits under the Scotland Act passed earlier this year.

Mr MacAskill has also called for additional powers to be devolved, allowing Scots police officers to conduct random breath tests on motorists, not just those whose driving caused suspicion.

Labour justice spokesman Lewis Macdonald said there was strong evidence to support calls for random testing and would not "in principle" oppose extra powers for Holyrood.

Tory Alex Johnstone said drink-driving was a "scourge on this country" but claimed cutting the limit would distract police from targeting the most serious offenders.

Scottish Liberal Democrat justice spokeswoman Alison McInnes MSP said: "It is concerning that the Conservatives have argued lowering the drink- driving limit could criminalise less serious behaviour.

"We must be clear there is no situation where being a little over the limit is acceptable. Reducing the drink-drive limit is a further step towards safer roads in Scotland.

"But setting the drink-driving limit is not a cure-all. The Scottish Government must go out of its way to educate drivers about the dangers of drink-driving."

MSPs backed the Government's consultation by 100 to 12, with the Tories opposing the move.

Mark Diffley, Ipsos MORI research director, said: "The Scottish Government has signalled its intention to lower the drink-drive limit and the public is broadly supportive of such moves.

"Although younger people are more likely to oppose the measure, it is clear that any reduction will enjoy the support of all groups and will be a largely popular policy."