Challenging drug-driving charge below legal limit

This is a really important question, and the answer depends on precisely what you mean by "below the legal limit" and which substance is involved.

Legal framework:

Drug-driving in England and Wales is governed primarily by section 5A of the Road Traffic Act 1988, which was inserted by the Crime and Courts Act 2013. This makes it an offence to drive, attempt to drive, or be in charge of a motor vehicle with a specified controlled drug in the blood or urine above the specified limit.

The specified limits for various drugs are set out in The Drug Driving (Specified Limits) (England and Wales) Regulations 2014. These limits differ depending on the substance. For example, the limit for cannabis (delta-9-tetrahydrocannabinol) is 2 micrograms per litre of blood, while for cocaine (benzoylecgonine) it is 50 micrograms per litre of blood. The limits for prescribed medications such as morphine and diazepam are set at higher thresholds to allow for legitimate therapeutic use.

If you are genuinely below the specified limit:

If your blood sample result came back below the relevant specified limit for the drug in question, you should not be convicted under section 5A. The prosecution must prove that the concentration of the specified drug in your blood exceeded the prescribed limit. If the result is below, the charge under section 5A should not succeed.

In practice, the Crown Prosecution Service should not proceed with a section 5A charge where the analysis shows the concentration is below the limit. If the charge has been brought despite the result being below the limit, this is a strong basis for the case to be discontinued or for you to be acquitted at trial.

However, there are some important nuances:

1. The prosecution might instead charge you under section 4 of the Road Traffic Act 1988, which is the older offence of driving while unfit through drugs. This offence does not depend on exceeding a specified limit. Instead, it requires proof that your ability to drive properly was impaired by a drug. Evidence such as erratic driving, poor performance on a roadside impairment test, or observations by officers can all be used. So being below the section 5A limit does not protect you from a section 4 charge if there is evidence of actual impairment.

2. You should check exactly which offence you have been charged with. The charge sheet or requisition will specify the section of the Act. If it is section 5A, the concentration is central. If it is section 4, the focus shifts to impairment.

3. Even under section 5A, you should check whether the blood sample was taken and analysed in accordance with the correct procedures. There are strict procedural requirements for the taking, handling, and analysis of blood samples. Failures in the chain of custody, delays, contamination, or irregularities in the statutory warning procedure can all provide grounds for challenge. You are also entitled to have your portion of the blood sample independently analysed.

4. Section 5A(3) provides a statutory medical defence. If the drug in your system was prescribed or supplied to you for medical purposes and you took it in accordance with any directions given by the prescriber or any accompanying instructions, and your driving was not impaired, you may have a defence even if the level was above the limit.

Practical steps:

1. Obtain the full evidence from the prosecution, including the certificate of analysis showing the exact concentration, the statement from the analyst, the custody record for the blood sample, and the police officers' statements.

2. Check whether you still have your portion of the blood sample and whether it can be independently tested if there is any dispute about the result.

3. Confirm which offence you are charged with, whether section 4, section 5A, or both.

4. If the result is below the specified limit and you are charged under section 5A, raise this with the prosecution at the earliest opportunity, as the case should not proceed.

5. If the charge is under section 4, consider whether there is any credible evidence of actual impairment, because the prosecution would need to prove that.

6. Consider instructing a solicitor who specialises in motoring offences if you have not already done so, particularly if the case involves procedural issues or if you are facing both charges.

Overall position:

Being below the specified limit is a very strong position if you are charged under section 5A. But it is not a complete shield because the prosecution can pursue a section 4 impairment charge independently, and the question then becomes whether there is evidence that your driving was actually impaired. The distinction between these two offences is critical, and understanding which you face is the first step to working out your best defence.