I wouldn't get too carried away by these statutory rules. For my entire career it has always been an offence to drive whilst unfit to drive for any reason. The section 4 offence covering driving on drugs had the effect of people losing their driving licence without a person being convicted of an offence. People would pass an alcohol test but appear to be under the influence of something. The lucky doctor on duty would then be called to assess whether the state of the patient as observed at that time meant him unfit to drive. More often than not the doctor knows what kind of drug might be involved and indicated that to the police officer. Then the weirdness sets in. The police could order a drug test which costs money and even if it came back positive was mostly of little value because the prosecution had to prove that the observed state or behaviour was caused by the drugs. Few cases got to court but people would lose their licence and not just for a year but very often for life. How, you may ask? The doctor on duty or the police officer would tell the driver to discuss the incident with his GP in some cases and in others, where there is clearly a problem, report it directly to the GP. In most cases the GP would discuss it with the patient and tell them they should not drive because of the drugs they are taking or the illness they have. If the patient was stubborn they would be offered a second opinion which was always the same as the first. If the patient continued to drive the doctor had the right and professional duty to report the patient to the DVLC (as was) or the DVLA. We didn't have to report them but the professional guidance was to consider the risk to health of the patient and others and inform the authorities if continued driving posed a significant risk. A while ago it became mandatory for doctors to inform the authorities. Younger people on drugs very often wouldn't see their GP and repeated stops with blood tests would accumulate enough evidence for a conviction if they hadn't already died as they drove off a bridge. All that is happening now is that strict liability is being introduced with the named drugs. Many of the people taking these drugs have already been advised that they should not be driving and if they continue to do so the person is more likely to lose his licence as a result of interaction with a GP than with the police.
Can I introduce you to the concept of the paragraph
I think most people are aware of the 'unfit through drink or drugs' rule. It was always my understanding that technically you could still be prosecuted for driving whilst unfit through drink even if you blew under the limit but that in practice prosecution would be very unlikely to be succesful.
It seems that up until now, alcohol aside testing for other drugs on the road side at least has been nothing more than subjective clap trappery and even at the station relies on the opinions of a random doctor to decide of a blood test is appropriate or not.
I'm not surprised it's taken the best part of 17 years for them to get to this point, the idea of 'legal' limits for 'illegal' drugs can't have been an easy thing to shoe horn into law. However it seems they spent so much time working on that they forgot to provide the extensive, credible research that would show people what effect these arbitrary levels of evil drugs would have on anyone's driving .
