The AA said as many as 400 morning-after drivers were caught during 2011.

A previous AA/Populus survey of more than 11,000 drivers found that 34 per cent felt they could often be over the legal limit the morning after and 46 per cent reckoned they might occasionally be over the limit.

AA president Edmund King said: "Too many drivers are caught out by being over the limit the morning after the night before.

"One unit of alcohol takes about one hour to get out of the system. However this is not a precise science as it depends on size, gender, whether you have eaten, state of your liver, metabolism and even mood.

"There is also confusion over units of alcohol due to varying strengths of beers and wines and different sizes of glasses. Our advice remains - if in doubt, don't drive."

Road safety campaigners Don't Be That Someone has also issued a strong message during this festive season. They have called on the government to enhance its efforts to change people's views on drink driving.

The road safety campaigners believe that the problem must be tackled by teaching under-18s about the dangers and effects driving while over the legal limit can have.

Michael McAdam, founder of Don't Be That Someone, said: "We welcome a yearly Christmas drink drive campaign. But it doesn't go far enough to tackle the serious problem of drink-driving.

"You need to educate young people to change their fundamental attitudes to stop them drink-driving in the first place, or you're not fixing the problem. We need specific educational and awareness campaigns aimed at pre-drivers."