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Drugs and Driving the New Law

Alcohol is of course a drug and we are all familiar with the laws that govern our use of it. New laws which come into force on 2nd March 2015 extend those rules to controlled drugs and prescribed medicines.

 We regularly advise in cases where people have been arrested for driving while the level of alcohol in their blood is said to be over the legal limit, or for being in charge of a vehicle when over the limit.

The consequences of conviction in such cases are extreme. For the driving offence a minimum ban of 12 months and if in charge a minimum of 10 points on your licence. The police have to follow strict rules when administering the testing procedure before charging a person and our starting point is always to check carefully to make sure the rules have been observed.

The Police can use evidence from breath, blood or urine samples and different procedures apply in each case.  Most charges are based on the breath test procedure using equipment like the Lion Intoxilyser which produces a reading showing the proportion of alcohol in a person’s breath.  However many issues can arise for example, someone may have been drinking after they finished driving.

In these cases we will often call expert evidence to prove what the levels would have been when driving.

From the 2nd March 2015 the need for expert evidence and legal advice is likely to be much greater. New offences of driving or being in charge of a motor vehicle with a concentration of a specified drug above a specified limit are introduced.

The offences carry the same penalties as the related drink offences but many questions arise;

  • Section 5A[3] provides a statutory defence if it is shown that the drug was prescribed for medical or dental purposes, taken in accordance with directions and that possession of it before taking it was not illegal.
  • The defence is not available if directions are not observed, but
  • It is enough for a defendant to raise the issue. It will then be for the Prosecution to establish beyond reasonable doubt that the defence case is not established.

There is currently only one approved screening device which gives a preliminary indication for up to 6 controlled drugs. It seems that in other cases the Police will still have to rely on field impairment tests to raise reasonable grounds for requesting a blood sample which can then be sent for testing. It remains the case that failure to cooperate with a screening enquiry is itself an offence carrying 4 penalty points.

At the moment the statutory limits relate to blood only. We have to wonder what happens where blood is not taken, for example because a person has a legitimate fear of needles. Will more seek to give urine samples?

It is clear that those drafting this legislation have sought to protect the many thousands taking prescribed medicines from unnecessary prosecution, but it remains to be seen how things will actually work out.  The message is clear; always check with your Doctor or health service provider about the use of any prescribed drug. Do not stop taking medication because of this legislation. Do contact Cartwright King for advice if you are in any doubt about your rights or are facing a prosecution under this legislation.

Table of drugs and limits

‘Illegal’ drugs (‘accidental exposure’ – zero tolerance approach)

Threshold limit in blood





delta-9-tetrahydrocannibinol (cannabis)




lysergic acid diethylamide






6-monoacetylmorphine (heroin)



‘Medicinal’ drugs (risk based approach)

Threshold limit in blood



















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