More than four in 10 (42%) drivers say they don’t know the legal drink-drive limit in England, Wales and Northern Ireland, equating to over 15 million drivers.

Millions of drivers could be getting behind the wheel while over the drink-drive limit, according to IAM RoadSmart

The survey of 1,004 motorists by IAM RoadSmart also found only around one in five (23%) correctly guessed the correct drink-drive limit in England, Wales and Northern Ireland – which is 35 micrograms per 100 millilitres of breath.

Meanwhile, awareness of the limit in Scotland was higher, with six in 10 (60%) of those surveyed knowing that it’s 22 micrograms of alcohol in 100 millilitres of breath.

The data indicates that millions of drivers could be getting behind the wheel while over the drink-drive limit, according to IAM RoadSmart.

Neil Greig, director of policy and research at the road safety charity, commented: “Our research highlights that there is still a real lack of awareness regarding how much alcohol is too much before it is illegal to drive.”

He added: “We would like to remind drivers that individual characteristics such as body weight, food consumption, gender and metabolism will also have an impact on the reading. This is why we will always recommend ‘none for the road’.”

The survey’s findings have also led the charity to reiterate its plea to the Government to roll out a smarter package of longer-term measures to help drive down the number of drink-drivers on Britain’s roads.

This includes a lower drink-drive limit across the UK, in line with Scotland’s system, a fast track of evidential roadside testing machines to release police resources and compulsory drink-drive rehabilitation courses for all drivers caught over the limit.

Greig concluded: “A prosecution for drink-driving will impact the rest of your life through public humiliation, loss of earnings, family break-up and a criminal record, as well as adding real danger to our roads.

“At IAM RoadSmart we estimate that the last drink that takes you over the limit could cost you up to £70,000!  If that isn’t a sobering thought, then nothing is.”

His comments follow last week’s call from a leading road safety campaigner for the drink-drive limit in the UK to be reduced by three-quarters to remove “legal but lethal” drivers from our roads.

Hunter Abbott, a breath alcohol testing expert and member of the Parliamentary Advisory Council for Transport Safety (PACTS), pointed out the current limit in England, Wales and Northern Ireland is the highest in Europe and the joint highest anywhere in the developed world. He also said it’s far above the ‘point of intoxication’ where significant measurable effects on cognitive function start to occur.

Last year saw the Parliamentary Advisory Council for Transport Safety (PACTS) speak out to say that the UK’s system to prevent drink-driving is no longer adequate and needs a major review – including a lower limit and improved enforcement.

Drivers are also reminded that Police Scotland is currently running a drink-drive blitz, clamping down on summer drinking. Its campaign runs for two weeks until 17 July. During its last crackdown in December, police tested 2,965 drivers, with 628 detected over the limit.