Drug Driving Defences

There are a number of Drug Driving Defences, we don’t propose to go through every available defence but here are a few of the more popular ones. If you think you may have a defence and want to avoid a ban call us on 01623 600645

It is a defence if you can show that you are taking the drugs as prescribed.


There is concern that this will criminalise patients who will then be put under the burden of establishing that they are taking the drugs as prescribed. DVLA will add the following advice to their ‘At a Glance’ pages:

“If you are currently being treated with or start being treated with diamorphine or ketamine, please be aware that it may be helpful to keep confirmation of this with you when you are driving. This is because the police have new powers to investigate drivers who are suspected of driving with such substance(s) in their bodies. If the police are satisfied that you are taking it under the supervision and/or advice of a healthcare professional (such as the prescriber, your doctor or pharmacist) and your driving is not impaired, they can allow you to proceed. Documents that you may find helpful to produce could include a prescription, counterfoil or any letter, report or advice from a healthcare professional. Please note that it remains your responsibility to refrain from driving if the medicine you are taking adversely affects your driving.”

Few defence solicitors will be easily persuaded that the police will simply let people go upon them showing a letter. Bear in mind that it will only become an issue when the police believe there is some evidence of impairment or bad driving will they simply abandon that once they see a letter saying the person is prescribed a drug or will they want to have the driver give a blood sample back at the police station so they can analyse the quantity involved. I believe this will lead to a lot more vulnerable, ill people being brought into the criminal justice system and put through the trauma of attending a police station under arrest.

In the Public Bill Committee on the Bill for this Act the Minister said as follows:

“In addition, under the Code for Crown Prosecutors, the public interest should clearly be taken into account when a prosecution is put forward. Furthermore, the Government expect that the courts will take a sensible approach to the operation of the new offence. For example, a defendant seeking to rely on the medical defence may be afforded more or less leeway depending on the facts of a particular case, such as the nature of the medical advice provided and the wording on the accompanying leaflet. It is certainly not our intention to try and catch out every person who has not read the microscopic lettering on the back of a very long white leaflet.” Whether the Prosecution or Courts take a similar view to that will be interesting. It will be important to remind the court of this comment by the Government when defending someone on this basis. If this affects you, see how, as expert Drug Driving Solicitors we can help.


Post driving consumption

As with drink driving cases some people will be arrested after they have arrived home, sometimes several hours after. In this situation the defendant is entitled to say ‘I stopped driving a while ago and took the drugs after I drove. They will have to obtain an experts report to show that they would have been under the limit at the time of driving. Whilst this is a fairly simple exercise for alcohol it is a lot more difficult for drugs, it remains to be seen how experts and the court will deal with this matter. If the consensus amongst the experts is that you cannot accurately do this test is it fair that defendants will be convicted simply because the science is not available?


Sufficiency of blood sample

It is not uncommon for a health care professional to be only able to obtain a small amount of blood. Given that there appears to be no option for urine I see many potential difficulties in this area.

If the health care professional is unable to obtain enough blood and there is no alternative to go to urine how will the defendant be charged with failing to provide a sample. The defendant will have a strong defence on the basis that he had a reasonable excuse for failing to provide, namely that through no fault of his the health care professional was unable to take a sample.

The Government is considering changing legislation to allow the use of vacutainers, which are more commonly used in the health sector and would allow blood kits to be used to collect more blood. In the meantime the Government’s expert advice is that 5ml vials will be sufficient provided 5ml of blood is collected. The Government also recognises that whatever volume of blood is obtained, it must be divided equally between the defendant and the prosecution.

The CPS have accepted that the lack of an alternative to a blood sample was likely to increase the number of prosecutions and trials for the offence of failing to provide a specimen under section 7(6) of the Road Traffic Act 1988.

If you want to fully explore Drug Driving Defences call us on 01623 600645 for free initial advice.