Road traffic police were out in numbers in Dumbarton and the Vale over the weekend advising motorists on the new limit as they put the road safety message across.

The limit which was previously 80mg of alcohol in 100ml of blood, or 35mg of alcohol in 100ml of breath, has been reduced to 50mg.

Several hundred cars were stopped across Scotland on Monday and traffic police carried out safety checks in Dumbarton and the Vale.

A checkpoint was set-up on Glasgow Road in Dumbarton.

Inspector Adam McKenzie, divisional road policing inspector for Argyll and West Dunbartonshire, oversaw the early-morning operation and he believes that motorists are getting the message.

He said: “We are sending out a message on road safety in general, advising drivers to check their tyres, wipers and lights and reminding them that the drink drive limit has changed.

“The new limit will save lives and that is what it is all about at the end of the day — saving lives and keeping people safe.” Under the new alcohol limit, a solitary drink could be enough to put some drivers over the limit and police are warning members of the public not to put themselves – or others – at risk.

A pint of beer or a small glass of wine could be enough to put an average-sized man over the limit, with an average-sized woman needing less than that to exceed the new legal limit.

On average 20 people are killed due to drink driving each year in Scotland and a further 90 are seriously injured.

Many more drivers could now be caught out the morning after a night on the tiles.

The message from the police is clear, if you are going to drink alcohol then leave the car at home.

Inspector McKenzie added: “We will be continuing to carry out random checks at further locations throughout West Dunbartonshire and if you decide to drink and drive then the chances are that you will be caught. It’s not worth the risk.

“You could end up losing your licence and with a criminal conviction on your record for the next 20 years. For the price of a taxi home or stopping drinking earlier, it just isn’t worth it. This morning we have already had a man detained in Clydebank in relation to drink driving.” The new breath-test limit is 22mg per 100ml of breath, where before it was 35mg.

Drivers coming from south of the border could also be caught out as the limit for the rest of the UK is set to remain unchanged for the time being.