Christmas is looming and with it comes the fear among bosses of drink-driving that's as inevitable as the post-turkey paunch.

Ahead of the government anti drink-drive campaign, the road safety charity Brake has issued guidelines on drinking alcohol.

An accompanying note of caution is that everyone is different and the advice here are merely guidelines: the safest advice is not to drink if there is any chance you will find yourself behind the wheel of a vehicle in the forseeable future.

But just how long does it take alcohol to leave your system? Here is Brake's guide.

Beers and ciders

Average strength beers and ciders like Fosters and Guinness are 2 hour pints.

Each pint takes at least 2 hours to leave your blood stream from when you stop drinking.

5.5% beers and ciders

Stronger beers and ciders like Stella, Kronenberg and Strongbow are 3 hour pints.

Each pint takes at least 3 hours to leave your blood stream.

 

Drink 4 pints of Stella and you can’t drive for at least 13 hours from finishing your last pint.

If you finish at midnight, you aren’t safe until after 1pm the next day.

Bottles

250ml – 330ml bottles of 5.5% beer
Becks, Bud and Stella bottles of this size and strength are 2 hour bottles.

Large 550ml bottles of beer
A large Stella or Newcastle Brown Ale in a 550ml bottle is a 3 hour bottle.

Drink 5 bottles and you can’t drive for at least 16 hours.

That’s 4pm the following day if you finish drinking at midnight.

275ml – 330ml alcopops
A standard Bacardi Breezer o rVodka Ice is a 2 hour drink. But bear in mind, it’s easy to drink a lot because they taste sugary,

Cans of beer or cider
A 3%-4% can of Carling or Fosters is a 2 hour drink. A 5%-5.5% strength can is a 2.5 hour drink.

Super strength cans of beer or cider
You can see why they have the reputation of being the favoured tipple of alcoholics.

Cans such as Special Brew, Tennent’s Super and Strongbow Super can be TWICE as strong as a Fosters – a whopping 7.5-9%.

A 7.5% can is a 3.5 hour drink. A 9% can is a 4 hour drink.

Drink 5 super-strength cans and you can’t drive for about 21 hours - almost a full day later.

Measures of spirits

It doesn’t matter what mixer you use.

The alcohol takes the same amount of time to leave your system whether your vodka’s just on ice or in a large glass of orange juice.

Pub measures vary. 25ml (one unit) used to be standard, but 35ml is now more common.

A 25ml shot is a 1 hour drink. A 35ml shot is 1.5 hour drink. A 70ml double is a 3 hour drink – the same as a pint of Stella.

Drink four 70ml doubles and you can’t drive for 13 hours – that’s 1pm the next day if you drank your last double at midnight.

If you are pouring spirits yourself at a party, you’ll probably pour generous doubles, triples or more. Take this into account when calculating your hours.

Glasses of wine

There are several different wine glass sizes and wine comes in different strengths, from 12%-15%. One 250ml glass of 15% wine is a 4 hour drink.

Drink a bottle of 15% wine - just three

250ml glasses - and you can’t drive for 13 hours - 1pm the next day if you finish at midnight!