Drug Driving Laws in the UK: Limits, Defences and Penalties

Driving in England, Wales or Scotland with certain controlled drugs above a specified blood limit is a standalone offence under section 5A of the Road Traffic Act 1988, while Northern Ireland still relies only on the older offence of driving while actually impaired by drugs.

This article covers the specified drug limit offence under section 5A of the Road Traffic Act 1988, as it applies in England, Wales and Scotland, and the separate impairment based offence that applies in Northern Ireland under the Road Traffic (Northern Ireland) Order 1995.

The offence: specified drug limits in England, Wales and Scotland

Section 5A of the Road Traffic Act 1988, inserted by the Crime and Courts Act 2013, makes it an offence to drive, attempt to drive, or be in charge of a motor vehicle with a specified controlled drug in your body above the specified limit for that drug. The section sets out the offence structure; the actual list of specified drugs and their limits is set by separate regulations for each nation.

England and Wales have applied specified limits since the Drug Driving (Specified Limits) (England and Wales) Regulations 2014 took effect on 2 March 2015. Scotland adopted its own equivalent regulations later: the Drug Driving (Specified Limits) (Scotland) Regulations 2019 came into force on 21 October 2019. The two sets of regulations specify the same 17 drugs at identical limits, including cannabis (THC), cocaine, ketamine, LSD, methamphetamine, MDMA and several prescription medicines such as diazepam and morphine, each measured in micrograms per litre of blood.

The medical and prescription defence

Section 5A(3) sets out a statutory defence where the specified drug had been prescribed or supplied to the driver for medical or dental purposes, and it was taken in accordance with the directions given by the person who prescribed or supplied it and with any accompanying instructions, provided the driver's possession of the drug was lawful. Section 5A(4) removes this defence where the driver had been advised, by the prescriber or on the medicine's instructions, not to drive for a period after taking it and drove within that period regardless. Section 5A(5) puts the burden on the prosecution once the defence is raised: the court must treat the defence as satisfied unless the prosecution proves beyond reasonable doubt that it is not.

If you take a prescribed or over the counter medicine as directed and it does not affect your ability to drive safely, this is not automatically an offence, but GOV.UK's own guidance still recommends talking to your doctor or pharmacist about whether a medicine affects your fitness to drive, since that is a medical judgement rather than a legal one.

Penalties for drug driving in England, Wales and Scotland

On conviction, GOV.UK states the penalties include a minimum one year driving ban, an unlimited fine (in Scotland the maximum fine is £5,000), up to six months in prison, and a criminal record, and the conviction will show on your licence for 11 years. A conviction also significantly increases insurance costs going forward and can affect your ability to travel to some countries, including the United States. The maximum penalty for causing death by careless driving while under the influence of drugs is life imprisonment.

Northern Ireland: an impairment based offence, not a specified limit

GOV.UK's own guidance states plainly that the specified drug limits law does not cover Northern Ireland, though a driver can still be arrested there if they are unfit to drive. The Road Traffic (Northern Ireland) Order 1995 contains an offence of driving, or being in charge, while under the influence of drink or drugs, but no article setting specified controlled drug limits equivalent to section 5A of the Road Traffic Act 1988.

In practice this means Northern Ireland has only the impairment offence, which England, Wales and Scotland also keep (section 4 of the Road Traffic Act 1988) but supplement with the specified limit offence: in Northern Ireland police must show the driver was actually impaired, typically through a Field Impairment Test followed by arrest and a blood test, rather than simply that a drug was present above a set limit. Nidirect's own guidance on drug driving describes only this impairment based offence and states the penalties as a minimum one year driving ban, a fine of up to £5,000, and possible imprisonment. Northern Ireland's maximum fine for this offence is £5,000, the same cap as in Scotland, while England and Wales have an unlimited fine; all three share the minimum one year driving ban.

Related reading: the section hub for UK driving laws, the separate drink driving limit, and what a drink driving ban involves.

Frequently Asked Questions

Is drug driving illegal everywhere in the UK?

Yes, but the offence works differently by nation. England, Wales and Scotland use a specified limit offence under section 5A of the Road Traffic Act 1988. Northern Ireland uses an older offence that requires proving the driver was actually impaired.

Can I be prosecuted for drug driving if I take prescribed medicine?

Not automatically. Section 5A includes a statutory defence for a drug that was lawfully prescribed or supplied for medical purposes and taken in accordance with the directions given, unless you were also advised not to drive and did so anyway.

What is the penalty for a drug driving conviction?

In England and Wales, GOV.UK states the penalties include a minimum one year driving ban, an unlimited fine, up to six months in prison and a conviction shown on your licence for 11 years; in Scotland the same applies except that the maximum fine is £5,000. In Northern Ireland, nidirect states a minimum one year ban, a fine of up to £5,000 and possible imprisonment.

Does Northern Ireland have the same drug driving limits as the rest of the UK?

No. Northern Ireland has no specified drug limits regime; it relies on an impairment based offence, meaning police must show the driver was actually unfit to drive rather than simply over a set limit.

How long does a drug driving conviction stay on my licence?

GOV.UK states a drug driving conviction is shown on your licence for 11 years in England, Wales and Scotland.