Drink-Driving Law in the UK

This section is intended as a brief summary of the current law relating to drink-driving in the United Kingdom. I am not a lawyer and I make no undertaking as to the accuracy of this information. If you need detailed legal advice I recommend you consult a solicitor. Links to several firms of solicitors specialising in drink-driving cases can be found on the links page of this site. The Resident Lawyer website, operated by a firm of solicitors, offers basic legal advice on drink-driving cases.

The Legal Limit

The UK legal limit for drivers is 80 mg of alcohol per 100 ml of blood, often referred to as a BAC or blood-alcohol concentration. In US terms this would be expressed as 0.08%. This is alternatively expressed in terms of breath alcohol - 35 g (microgrammes) per 100 ml (which is now the usual official measure in the UK), or alcohol in the urine - 107 mg per 100 ml.

This is often reckoned to be equivalent to two pints of ordinary strength beer which, for a man of average weight, is broadly true, but should not be used as a general rule - see Drink-Driving Guidelines. It is impossible to draw an accurate correlation between the amount of alcohol consumed and the resulting peak BAC, and anyone trying to "drink up to the limit" runs a serious risk of exceeding it.

It is also possible to be charged with driving or attempting to drive under the influence of drink or drugs even with a BAC level is below 80 mg. Such cases are rare but not unknown. In addition, a BAC level not far below 80 mg is likely to be regarded by the courts as an aggravating factor if charges are brought for causing an accident.

In 1998, the UK government issued a consultation paper proposing the reduction of the UK legal limit from 80 mg to 50 mg, but after lengthy deliberations announced in March 2000 that they were not going to proceed with this for the time being, pending a European Union Review - see 80 mg Limit to Stay (for now).

Police Powers

For the police to be able to require a breath test, a driver must have either:

(a) committed a moving traffic offence, e.g. speeding, failing to observe a stop sign, having a defective light etc.,
(b) have been involved in an accident to which the police were called, or
(c) have given the police grounds to suspect they had consumed alcohol above the legal limit, e.g. by draving erratically or walking unsteadily before getting into the car. It is questionable whether the mere fact of having driven out of a pub car park constitutes reasonable grounds for suspicion

Although there have often been calls for the police to be given "unfettered discretion" to administer breath tests, this has never been implemented. However, in practice the police interpret the powers above very liberally - and who never exceeds the speed limit by at least a few mph? It is difficult to conceive of circumstances under which the current law prevents police from carrying out a breath test where they believe there is any chance of obtaining a positive result.

Although there are restrictions on police powers to require breath tests, the police are entitled to stop any vehicle without giving a reason. This allows them to operate anti drink-driving roadblocks, particularly over the Christmas period.

What the police would typically do is to set up an checkpoint, and then stop vehicles at their discretion - which they are perfectly entitled to do. They will then ask the driver whether he has been drinking. If he says "yes", or "just the one", then they have grounds for suspicion and will administer a breath test. If he says "no", the police officer replies "then you won't have any objections to taking a breath test, will you Sir?" While the driver is entitled to refuse, most people - particularly if they were confident they had nothing to fear - would decide that discretion was the better part of valour, and accede to the test. Few people want to be branded as a troublemaker in the eyes of the police. This is pushing the existing powers beyond where they were intended to go, but has now become a widely-used tactic.

The law applies to a "road or public place", so you can be convicted of drink-driving anywhere the public have access, including private car parks - you do not have to be on a public road. Specifically, and contrary to popular myth, the police can require a breath test on a pub car park. However, it is not a specific offence on private land to which the public do not have access, although various charges could be brought if driving under the influence of alcohol led to death or injury.


The police officer at the roadside will administer a screening breath test using a digital breathalyser. This uses a "traffic light" system under which green indicates no alcohol present, amber some alcohol but below the legal limit, and red alcohol possibly above the legal limit. A refusal to provide a specimen at this point is an offence, but of itself does not lead to mandatory disqualification, particularly if you subsequently provide a specimen at the police station. This is partly to deter wasting police time.

If your reading is red, you will be arrested on suspicion of drink-driving and required to take a further test at a police station. You cannot be convicted purely on the evidence of the roadside breath test. If the police officer is in a car, he might take you directly to the police station, but more likely (and certainly if he is on a motorcycle) he will call for another police vehicle to attend the scene to provide transport.

At the police station, you will be required to provide two breath samples for the Intoximeter equipment, which is accurately calibrated and is used to provide the evidence of your BAC that is presented in court. The reading that will be used is the lower of the two samples. At this stage, a refusal to provide a specimen is an offence that is treated in law as the equivalent of being convicted with a BAC above the legal limit.

If your breath-alcohol level is between 40 and 49 g, you will be offered the opportunity to take a blood or urine test as an alternative. This option should always be taken, as you have nothing to lose, and there is a chance it may result in a more favourable figure, particularly if you consider your alcohol level is falling. If the police fail to offer this alternative they have not applied the procedure correctly and this can be used as a defence in court. You also have the right to be given a sample of blood or urine for independent analysis, but experience suggests that the alcohol level is unlikely to vary significantly from the official test.

In practice, prosecution guidelines followed by the police mean that drivers are not normally prosecuted until they reach 40 g of alcohol per 100 millilitres of breath, equivalent to a blood alcohol level of over 90 mg. However, you should be aware that the police will prosecute for blood and urine alcohol levels of 1 mg over the legal limit, if the breath-alcohol level was above 40 g. This explains why press reports occasionally appear of individuals being prosecuted with a BAC of 81 mg, which seems to go against the discretion outlined above. It should also be remembered that the 40 g threshold is only a discretionary one, and the police may prosecute for a 36 g level if, for an example, a driver appeared to be very drunk, but gave an unexpectedly low reading.

To stop you from driving again while you are still over the limit, the police may keep you at the police station for some time. In some cases this can mean a night in the cells. Once you have been released from the police station you will be expected to make your own way home at your own expense, and also to retrieve your vehicle.


For any offence of driving or attempting to drive while over the prescribed alcohol limit, there is a mandatory minimum sentence of one year's disqualification. This can only be waived in very exceptional circumstances, such as if the offence was committed in response to a medical emergency, or if the offender would be completely unable to earn a living. A first offender will also receive a fine, typically around 300 - 400, although fines can be below 100 for offenders of limited means.

Magistrates have the power to impose longer periods of disqualification and are increasingly making use of this - in some cases 18-month bans have been imposed for BACs below 120 mg. The maximum sentence that can be imposed for driving with excess alcohol is a fine of 5,000, and a 6-month prison sentence, something that is not as widely appreciated as it should be.

If an offender has committed a second offence within a ten-year period, or has a BAC over 2.5 times the legal limit (i.e. 200 mg or above), they will be classed as a "high-risk offender". They will receive a three-year minimum mandatory period of disqualification, and before they can drive again will be required to satisfy a doctor - at their own expense - that they do not have an ongoing alcohol problem.

The penalties for refusing a breath or blood test at the police station are identical to those for a "standard" offence. However, the courts are likely to impose penalties well above the minimum for this offence - often a ban of eighteen months or two years - as refusal can clearly be used to conceal a very high blood-alcohol level.

There are also various charges relating to being "in charge" of a vehicle, but not driving or attempting to drive it. These do not carry mandatory disqualification, although the penalties can still be severe, typically 10 penalty points. The police often take a very broad view of attempting to drive - for example a man who had left his car in a pub car park, had too much to drink, and decided to retrieve his briefcase from the boot before phoning for a cab home, was convicted of attempting to drive, and disqualified.

You should be aware that if your car is parked in the street, you are committing an offence if you even so much as touch it while over the drink-drive limit. You should certainly not, for example, help to push it away from blocking a driveway.

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