Drink and drug driving in the theory test: legal limits and penalties
Updated •5 min read
The drink drive limit is 35 micrograms of alcohol per 100 millilitres of breath in England, Wales and Northern Ireland, and 22 in Scotland. The car theory test covers the effects of alcohol, drugs and medicines on driving.
The legal alcohol limits
gov.uk gives these limits and says the limits in Scotland are different to the rest of the UK (gov.uk: the drink drive limit).
| Level of alcohol | England, Wales and Northern Ireland | Scotland |
|---|---|---|
| Micrograms per 100 millilitres of breath | 35 | 22 |
| Milligrammes per 100 millilitres of blood | 80 | 50 |
| Milligrammes per 100 millilitres of urine | 107 | 67 |
gov.uk also says it is impossible to say exactly how many drinks this equals, because it is different for each person. How alcohol affects you depends on your weight, age, sex and metabolism, the type and amount of alcohol, what you have eaten recently and your stress levels.
gov.uk's penalties page also covers driving while unfit through drink, which is a separate offence from being over the limit. The simplest way to stay on the right side of both is not to drink if you are driving.
Drug driving
gov.uk says it is illegal to drive if you are unfit because of legal or illegal drugs, or if you have certain illegal drugs in your blood, even without visible impairment (gov.uk: drug driving law).
- In England, Scotland and Wales it is illegal to drive with legal drugs in your body if it impairs your driving.
- Driving with certain listed drugs above the specified limits is an offence if you were not prescribed them. The list includes amphetamines, several benzodiazepines, methadone, and opioids such as codeine, tramadol and fentanyl.
- You can generally drive on prescribed medicine if you took it as your healthcare professional advised and it is not making you unfit to drive.
- Even with a prescription, you can be prosecuted if a medicine leaves you unfit to drive, so ask your doctor or pharmacist if you are unsure.
The drug driving law does not cover Northern Ireland, but gov.uk says you can still be arrested there if you are unfit to drive.
Penalties
gov.uk lists these drink driving penalties (gov.uk: drink driving penalties). The magistrates hearing a case decide the actual penalty.
| Offence | Maximum penalty |
|---|---|
| Being in charge of a vehicle while over the limit or unfit through drink | 3 months in prison, a fine of up to £2,500 and a possible driving ban |
| Driving or attempting to drive while over the limit or unfit through drink | 6 months in prison, an unlimited fine and a minimum one-year ban (three years if convicted twice in 10 years) |
| Refusing to provide a breath, blood or urine specimen | The same penalties as driving over the limit |
| Causing death by careless driving while under the influence | Life imprisonment, an unlimited fine, a minimum five-year ban and an extended driving test |
For drug driving, gov.uk lists a minimum one-year driving ban, an unlimited fine, up to 6 months in prison and a criminal record. The conviction stays on your licence record for 11 years (gov.uk: drug driving law).
How the topic appears in the theory test
The regulations that set the car test subjects include the effects of alcohol, drugs, medicines, state of mind and fatigue under the heading "the driver" (legislation.gov.uk: Schedule 7). Our theory test topics guide lists all seven areas.
gov.uk does not publish the questions or say how many are about alcohol and drugs, so we do not give a number. In practice, learn what the sources above say: the effects on your driving, the fact that medicines count, and that legal limits do not make driving safe. The questions are based on the Highway Code among other books (gov.uk: revision and practice).
You do not need to memorise the full penalty table to understand the topic. Knowing that the consequences are serious, and that medicines can affect you too, is the useful part. If you want a plan for fitting this into your revision, see our how to revise guide.
Check your knowledge
The free theorytest.ai diagnostic shows which topics you lose marks on, including questions about the driver. theorytest.ai is independent and is not affiliated with the DVSA.
Frequently asked questions
What is the drink drive limit in England and Wales?
35 micrograms of alcohol per 100 millilitres of breath, 80 milligrammes per 100 millilitres of blood, or 107 milligrammes per 100 millilitres of urine.
Is the drink drive limit different in Scotland?
Yes. In Scotland it is 22 micrograms per 100 millilitres of breath, 50 milligrammes in blood and 67 milligrammes in urine.
Can I drive on prescribed medicine?
Generally yes, if you took it as your healthcare professional advised and it is not making you unfit to drive. You can still be prosecuted if it does.
What is the penalty for drink driving?
Driving over the limit can bring up to 6 months in prison, an unlimited fine and a minimum one-year ban, according to gov.uk.
Are alcohol and drugs in the theory test?
Yes. The regulations say the test covers the effects of alcohol, drugs, medicines, state of mind and fatigue on the driver.