You might not be safe to drive until the NIGHT AFTER the night before…

Did you know? On average, the body eliminates one unit of alcohol per hour

Can you imagine the shame? You had a few drinks the night before — a few too many, perhaps, but it was a special occasion.

By the time you have to go to pick up your children from school the following afternoon, the hangover’s gone and you don’t think twice about getting behind the wheel. And then it happens.

You’re pulled over by the police, told you’re suspected of drink-driving and asked to take a breath test. It proves positive, and you’re arrested and taken to the nearest police station to be tested again.

There, you’re told you’re one-and-a-half times over the legal limit and you’re charged with drink-driving.

That was the mortifying scenario that unfolded on September 10 for 44-year-old Victoria Sturdy, whose farmer husband, Julian, has been the Conservative MP for York Outer since 2010. The family home is in the well-to-do North Yorkshire village of Bilton-in-Ainsty, eight miles west of York, where the children go to school.

Last week, magistrates banned Mrs Sturdy from driving for 15 months and fined her £398. It was her first court appearance and, said her solicitor, it would be her last — in 27 years of driving she had never had so much as a speeding fine. 

‘She hadn’t the slightest inkling she was over the prescribed limit,’ her solicitor said.

And, with the Christmas party season approaching fast in the rearview mirror, there but for the grace of God go many others.

The legal limit for driving in England, Wales and Northern Ireland is 80 milligrams of alcohol per 100 millilitres of blood. In Scotland it’s only 50. Mrs Sturdy, who works as a part-time secretary for her MP husband, had 136 milligrams when she was pulled over on the school run after a tip-off.

She said she hadn’t drunk any alcohol for at least 14-and-a-half hours — since the early hours of that day. It was, said her solicitor, a ‘classic case’ of genuinely believing the alcohol was out of her system.

Depending on how much she’d had to drink the night before, that’s entirely feasible. On average, ‘the body eliminates alcohol at the rate of one unit per hour’, explains Richard Allsop, emeritus professor of transport studies at University College London. 

Fact: The legal limit for driving in UK is 80 milligrams of alcohol per 100 millilitres of blood

Fact: The legal limit for driving in UK is 80 milligrams of alcohol per 100 millilitres of blood

‘So anyone who wants to calculate by what time they are completely free from alcohol needs to find out, for each of the drinks they usually consume, how many units it contains, and then keep a tally for each drinking session.’

The calculation, which should begin an hour after your last drink to ensure the last of the alcohol is in the bloodstream, is not easy, says Fiona Sim, chief medical adviser at charity Drinkaware.

‘The rate at which alcohol is removed from the blood varies from person to person,’ she explains. ‘Your weight, age, sex and metabolism can all affect how long it takes — you also need to consider the type and amount of alcohol you’re drinking, whether you’ve eaten and your stress levels.’

Men generally process alcohol more quickly, while having food in your stomach will slow absorption into the bloodstream, ironically potentially keeping alcohol in your system longer.

Other factors include the state of your liver: if it has been damaged by regular heavy drinking, it will take longer to get rid of alcohol.

Oh, and there’s nothing you can do to speed up the rate at which alcohol leaves your system.

‘Black coffee or a cold shower will not sober you up,’ says Steve Horton, director of communications at Road Safety GB. ‘Coffee just means you’re awake and drunk and a cold shower that you’re cold, wet and drunk.’

Each 250ml (large) glass of wine of 12 per cent alcohol strength equates to three units. Drink six glasses in an evening — entirely possible at the office party — and you’ve consumed 18 units.

If you have your last drink at 11.30pm, it could be 6.30pm the following evening before all the alcohol in your blood has been processed. At 9.30am, you could still have nine units in your blood, putting you well over the legal limit.

Tony Moss, a professor of addictive behaviour science at London South Bank University, says motorists can avoid being caught out the following day by using a personal breathalyser before driving the next day.

‘Taking a reading after an evening’s drinking isn’t the way to use a breathalyser,’ he says.

‘Your blood alcohol level can carry on going up for a good hour or two after you stop drinking, so midway through the drive home you could find yourself over the limit.’

The only sensible time to use a personal breathalyser, says Professor Moss, ‘is the morning after’.

A poll by The AA in 2016 found one in five drivers admitted driving the morning after a drinking session — and, while the overall number of drink-driving prosecutions is falling, the proportion of morning-after cases is rising — 20 per cent of drink-drivers are now caught between 6am and midday.

 

Read more at DailyMail.co.uk