What are the drink driving limits in the UK?

Last updated by mustard.co.uk on April 22nd, 2021

It doesn’t take a genius to know that drinking and driving don’t exactly go hand in hand.

Even a small amount of alcohol can inhibit your ability to drive and if that happens, you don’t just risk having your licence revoked, you also put your own and others’ lives in danger.

And yet it’s safe to say that many people wouldn’t think twice about having a glass of wine with dinner, then getting in our car and driving home at the end of the night.

So how much alcohol can you really drink before it’s time to leave the car keys at home and call a taxi?

Drink drive limits

Alcohol affects everyone differently, so while one person may feel safe to drive after a drink or two, the same amount could put someone else well over the limit.

That’s why the safest bet is to not drink at all if you’re going to be driving.

That being said, it’s important to familiarise yourself with the drink-drive alcohol limits across the UK, so that you can make an informed decision as to whether you would be safe to drive after consuming alcohol.

Drink drive limits in England, Wales and Northern Ireland

• 35 micrograms of alcohol per 100 millilitres of breath
• 80 milligrams of alcohol per 100 millilitres of blood
• 107 milligrams of alcohol per 100 millilitres of urine

Drink drive limits in Scotland

• 22 micrograms of alcohol per 100 millilitres of breath
• 50 milligrams of alcohol per 100 millilitres of blood
• 67 milligrams of alcohol per 100 millilitres of urine

What is an alcohol unit?

Alcoholic drinks come in all different forms, strengths and sizes so it can be hard to measure how much alcohol you’re actually ingesting.

That’s why alcohol units are now the accepted and preferred way of measuring the alcoholic content of a drink, with a unit being defined as 8g or 10ml of pure alcohol.

The human body takes about an hour to break down each unit of alcohol consumed, although the exact time varies from person to person.

Two pints of beer on table

A large glass of wine counts as around three units, a pint of lager is around 2.5 units and a single gin and tonic is one unit.

So if you drink three glasses of wine on a night out and finish your last drink at midnight, then you shouldn’t be going anywhere near your car until at least 9am the next day.

And if you’ve drunk more than that, you could still have alcohol in your system 24 hours later, so never assume that you’re ok to drive just because it’s the day after a big night out – you could still quite easily be over the limit.

How does alcohol affect my driving?

Every person reacts differently to alcohol because factors like age, weight and height affect how quickly it enters the blood stream.

The speed at which your body absorbs alcohol can also very depending on what you’ve eaten and how recently, the amount of stress you’re under and whether you are male or female.

Anyone who’s ever been drunk will know that you often can’t tell when alcohol begins to affect you, which is exactly why drink driving is so dangerous.

You may think that you feel fine but in reality, even from the first drink your reactions will begin to slow down and your coordination will start to suffer, both of which are vital for driving safely.

Your vision will worsen and become blurred, you’ll begin to feel tired and the way that your brain perceives speed and distance will become impaired.

In fact, having alcohol in your system will affect almost everything you need in order to drive safely, including your memory and ability to make quick, calculated decisions.

What happens if I get caught drink driving?

If the police suspect you may be driving drunk, they can pull you over to the side of the road and ask you to take a breathalyser test.

This measures the amount of alcohol in the air you breathe out but it isn’t completely fool proof, so even if the test shows no alcohol, you may be asked to provide a urine or blood sample so your blood alcohol content (BAC) can be checked.

If you are convicted of drink driving, you could be met with a £2,500 fine, banned from driving, or even given a prison sentence.

If that wasn’t enough, having a drink driving conviction is a red flag to insurance brokers and tells them that you’re a major risk, which means your premium is likely to be sky high.

If you like to play it safe, help is at hand from a small number of companies building handheld breathalysers you can use at home. That means you can test yourself before you drive. This will give you peace of mind and is way less costly than the fine you’ll receive, should you get caught over the limit. You can find our recommended, tried and tested breathalyser here.

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