The police want the drink-driving limit lowered.

The Association of Chief Police Officers head of roads policing, chief constable Steve Green said the limit should be lowered from 80 milligrams of alcohol in the bloodstream to 50 milligrams, in line with much of Europe.

It would be difficult, he added, to reduce the figure to zero as some people carry a residue of alcohol in their bloodstream.

"We thought we had got the message across, particularly to young people, that drink driving is unacceptable but we need to refresh that now," he said.

"In terms of random breath testing, I believe the police have always been able to do this.

"It is possible to stop a vehicle for any number of things and if an officer smells alcohol on the breath of the driver then they can ask them to take a breathalyser."