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For decades, drink driving was the offence most people associated with being stopped and tested at the roadside. New driving-licence data suggests that the balance has now shifted. In 2025, the number of endorsements for driving over a specified drug limit exceeded the equivalent drink-driving endorsements for the first time.

The figures are striking. DVLA data obtained and analysed by the road-safety charity IAM RoadSmart records 30,707 DG10 drug-driving endorsements in 2025, compared with 29,769 DR10 drink-driving endorsements. DG10 endorsements were 28% higher than in 2022, while DR10 endorsements fell by 17% over the same period.

IAM RoadSmart describes these as UK licensing figures. The explanation of the law below is limited to England and Wales, where Chetwode practises; the legal and testing arrangements are not identical throughout the United Kingdom.

The difference is still fairly narrow - 938 endorsements - but the direction of travel deserves attention. It reflects both a genuine road-safety concern and a form of prosecution that many motorists still misunderstand. A person may feel completely normal, pass a roadside impairment exercise and nevertheless be convicted because a laboratory later reports a specified drug above its legal limit.

The important qualification: the figures compare DG10 and DR10 endorsements. They do not count every drug- or drink-related motoring offence, and they do not by themselves prove that drug-impaired driving is now more prevalent than drink-impaired driving.

What does it mean to say drug driving has overtaken drink driving?

DG10 is the endorsement code used when somebody drives or attempts to drive with a specified controlled drug above the legal limit. DR10 is the corresponding code for driving or attempting to drive with alcohol above the prescribed limit. Comparing those two codes is sensible because both concern the measured concentration of a substance rather than a requirement to prove that the driver was visibly impaired.

The comparison is not, however, a count of every relevant offence. It excludes driving while unfit through drugs, which carries the DR80 code, and driving while unfit through drink, which carries the DR20 code. It also excludes offences such as being in charge, failing to provide a specimen and causing death by careless driving while under the influence.

An endorsement is an entry on a driving record following the court process. It is not a roadside test, an arrest or a charge. The year in which an endorsement is added may also be affected by the time taken to analyse blood and bring the case to court. The figures therefore provide a reliable picture of recorded outcomes for the two codes, but not a complete measurement of what was happening on the roads during 2025.

There are two principal drug-driving offences

Driving while unfit through drugs

Section 4 of the Road Traffic Act 1988 makes it an offence to drive or attempt to drive on a road or other public place while unfit through drink or drugs. For a drug case, the prosecution must establish that the person's ability to drive properly was impaired and that the impairment was caused by a drug. Evidence may come from the manner of driving, a collision, police observations, a field impairment test and medical or scientific evidence.

This offence is not limited to the drugs named in the specified-limits legislation. It can apply to illegal drugs, prescribed medication and other intoxicants. A person who has taken medicine exactly as directed may still commit the section 4 offence if it has in fact made them unfit to drive.

Driving above a specified drug limit

Section 5A, introduced for offences committed from March 2015, takes a different approach. It is an offence to drive or attempt to drive with the concentration of a specified controlled drug in the blood or urine above the limit set for that drug. The prosecution does not have to prove poor driving or actual impairment.

That distinction is central to the rise in DG10 cases. Before section 5A, proving drug driving often depended upon evidence that the drug had affected the individual driver. The modern offence allows the prosecution to rely upon driving, a qualifying location and an evidential blood result above the specified limit. In practical terms, it made many cases easier to identify, charge and prove.

How a roadside drug test becomes a court case

A roadside drug swab is a preliminary screening test, commonly used to indicate cannabis or cocaine. It is not normally the evidence that proves the concentration of a drug for a DG10 prosecution. Following a positive result, the police can take the driver to a police station and require an evidential specimen, usually blood. The sample is then analysed by an accredited laboratory.

A screening test may be required where an officer reasonably suspects that a driver has taken a drug, where a moving traffic offence has been committed or after a road traffic collision in the statutory circumstances. The fact that a high proportion of tested drivers receive positive roadside results must be understood in that context: the police are generally testing selected drivers, not taking a random sample of all motorists.

The laboratory result should account for the measurement uncertainty applicable to the drug being analysed. Drug concentrations are therefore commonly reported as being 'not less than' a stated figure. The driver should also be offered part of the specimen for independent analysis. That opportunity can be important where the result is close to the limit or there is a question about handling, storage or the analytical process.

What if the driver passes a field impairment test?

A field impairment test and a roadside drug swab serve different purposes. The first looks for signs that the person's ability to drive may be impaired. The second indicates whether a relevant drug may be present. Passing the impairment exercises does not cancel a positive swab and does not necessarily prevent a lawful requirement for blood.

This can feel counter-intuitive, but it follows from the difference between sections 4 and 5A. A good performance on an impairment test may assist in answering an allegation that the driver was unfit. It does not establish that their blood concentration was below the specified limit. Equally, a negative swab does not rule out every drug because roadside devices do not screen for all substances capable of impairing driving.

Cannabis and cocaine: low limits and no need to prove impairment

The limits for drugs commonly used illegally were set using a 'zero tolerance' approach while allowing for accidental exposure. In England and Wales, the specified limit is 2 microgrammes of THC per litre of blood for cannabis and 10 microgrammes per litre for cocaine. Benzoylecgonine, the principal cocaine metabolite, has a separate limit of 50 microgrammes per litre.

These limits should not be treated as the drug equivalent of the drink-drive limit. The Sentencing Council expressly recognises that the alcohol limit was set by reference to expected impairment, whereas the illegal-drug limits reflect a different policy. It is not possible simply to convert a cannabis or cocaine reading into a particular degree of impairment, and a higher reading does not map neatly onto the alcohol sentencing bands.

There is also no dependable rule telling a person that it will be safe to drive a set number of hours after taking a drug. Concentrations vary according to the substance, dose, pattern of use and individual metabolism. A driver may no longer feel an obvious effect but can still be above the legal limit.

What about prescription medication?

The specified-drug regime also covers medicines including diazepam, clonazepam, lorazepam, temazepam, methadone, morphine and amphetamine. The limits for the mainly medicinal group were set differently and are generally above concentrations associated with ordinary therapeutic use. Some patients, particularly those taking higher doses, can nonetheless produce a result above the limit.

Section 5A provides a medical defence where the drug was prescribed or supplied for medical or dental purposes, it was taken in accordance with the relevant professional directions and accompanying instructions, and possession was lawful. Once the defence is properly raised, the prosecution must disprove it beyond reasonable doubt.

Evidence matters. A prescription record, dispensing label, patient information leaflet and clear evidence of the directions actually given may all become important. Taking more than directed, using medication prescribed for someone else or combining it contrary to advice may defeat the defence. The defence also applies only to the specified-limit charge: it does not permit somebody to drive when the medication has actually made them unfit.

Why are DG10 endorsements rising?

The available figures cannot provide a single answer. Part of the increase is likely to reflect the structure of the section 5A offence and the growing use of roadside screening. Police officers now have a practical route from suspicion, to a quick oral-fluid indication, to evidential blood analysis. Greater awareness and more targeted enforcement will identify conduct that might previously have gone undetected or been difficult to prove.

There may also be a real increase in drug use among drivers. Department for Transport work on road fatalities found a broad increase between 2014 and 2023 in fatal collisions where police recorded 'impaired by drugs' as a contributory factor. In 2023 the factor was allocated in 124 fatal collisions, or 9.1% of fatal collisions where a contributory factor was recorded, compared with 47 and 3% in 2014. The Department warns that drug data is incomplete and difficult to compare directly with alcohol, but the trend cannot be dismissed as a licensing-record curiosity.

At the same time, the crossover is partly caused by DR10 falling. Drink driving has been the subject of sustained public education, familiar enforcement and a rehabilitation-course system for many years. The 2025 figures do not tell us how much of the change is caused by safer behaviour, altered enforcement, court throughput, greater drug use or improved detection. They tell us that the licensing system is now recording at least as many endorsements arising from specified-limit drug cases as from the equivalent alcohol offence.

What must the prosecution prove in a DG10 case?

The prosecution must prove that the defendant drove or attempted to drive a motor vehicle on a road or other public place and that the concentration of a specified controlled drug exceeded its legal limit. Cases can turn on the identity of the driver, whether the conduct amounted to driving or an attempt, whether the location was legally a road or public place, and the reliability and admissibility of the scientific evidence.

The procedure used to require and obtain blood can also matter. Relevant material may include the roadside-test record, body-worn video, custody documents, the MGDD forms, the healthcare professional's notes, the laboratory statement, continuity records and the unused portion of the specimen. A procedural error does not automatically end every prosecution, but the statutory requirements and the fairness and reliability of the evidence must be examined carefully.

Early advice is particularly valuable where independent analysis is needed. Drug concentrations can change if a specimen is not stored correctly, and expert instructions take time. Waiting until shortly before trial may make it harder to investigate a close result or identify a break in continuity.

What sentence can the court impose?

Driving or attempting to drive above a specified drug limit is dealt with in the magistrates' court. The maximum sentence is six months' imprisonment and an unlimited fine. Disqualification is obligatory for at least 12 months, unless the court finds a special reason relating to the circumstances of the offence. A relevant previous drink- or drug-driving conviction within the preceding ten years ordinarily increases the minimum ban to three years.

Under the Sentencing Council guideline, the least serious category has a Band C fine as its starting point and a disqualification normally ranging from 12 to 16 months. Cases involving greater harm or higher culpability move into community-order or custody territory, with longer bans. Obvious impairment, unacceptable driving, commercial driving and the presence of another specified drug or alcohol are among the features that can increase seriousness.

A DG10 endorsement remains on the driving record for 11 years. There is currently no drug-driving rehabilitation course equivalent to the drink-drive course through which an eligible offender can obtain a reduction in the period of disqualification. Beyond the sentence, a conviction can have substantial consequences for insurance, employment involving driving and professional or regulatory status.

What should you do if you are accused of drug driving?

Do not assume that the case is unanswerable simply because the prosecution has served a laboratory figure, but do not assume that feeling sober or passing an impairment test is a defence to an over-the-limit charge. The first task is to identify the precise allegation and preserve the evidence needed to test it.

Keep any paperwork given by the police, including information about the retained blood sample. If prescribed medication may be relevant, preserve the prescription history, packaging and the directions you were given. A solicitor can then check the legal basis of the requirement, the continuity and analysis evidence, any medical defence and the sentencing implications before important decisions are made about plea or expert evidence.

How Chetwode can help

Drug-driving cases are scientific prosecutions governed by detailed statutory procedures. The apparently simple question - was the result above the limit? - can conceal important issues about the offence charged, the roadside and police-station process, the evidential specimen, laboratory uncertainty, prescribed medication and the way in which the prosecution presents the reading.

London Drink Driving Solicitor represents motorists accused of driving while unfit and driving above a specified drug limit. We examine the procedure and scientific evidence, arrange expert analysis where it is justified and give clear advice about plea, trial and the risk to your licence. If you have been charged with drug driving, contact us promptly so that the blood evidence and available defence material can be considered before court deadlines begin to restrict your options.