IAM RoadSmart is calling on drivers to take more responsibility this festive period, on the back of a survey suggesting the majority are unaware of the amount of alcohol that will ‘tip them over the limit’.

The survey asked more than 1,000 motorists how many micrograms of alcohol are permitted in 100 millilitres of breath before they would fail a police breathalyser. On average, the answer was 52.

This is despite the fact the actual threshold is only 35 micrograms per 100 millilitres of breath.

Meanwhile, 50% of respondents said they were likely to get behind the wheel the next morning following festive drinks.

IAM RoadSmart says it is concerned by these admissions, and is calling on drivers to plan ahead and be extra careful over the festive period.

Neil Greig, director of policy and research at IAM RoadSmart, said: “Drinking and driving simply does not mix and every driver should plan to leave the keys at home rather than face a fine, lengthy ban or time in a police cell.

“Worryingly, the research also highlights that there is still real ignorance regarding how much alcohol is enough before it is illegal to drive. Although motorists may well think they know how many drinks will typically tip them over the limit, individual characteristics such as body weight, food consumption, gender and metabolism will also determine the reading.

“So, if you’re planning to drink alcohol at a Christmas celebration, do not try to calculate whether or not you are over the limit. It is always best to make it none for the road.”

The charity has also reiterated 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 to reinforce good behaviour, fast-track of evidential roadside testing machines to release police resources and tailored approaches to help drivers with alcohol problems.