I am concerned at some of the inaccurate information in this thread that, if taken as gospel, could land people in real difficulties.
It is not the case that being medically prescribed a drug allows you to drive with a higher concentration of drugs in your system. There is a presumption that people should not drive with any drugs in their system at all, but the legal maximums are specifically set to allow for people who are likely to have traces of drugs due to prescriptions.
It is not for individuals to determine whether or not they are fit to drive. There are prescribed limits that apply in all instances and you cannot drive above them, whatever the reason. Many drink and drug drivers are surprised that they are over the limit but, if they are, an automatic ban (minimum 12 months) follows. There is no discretion on this.
A little known fact is that the Police can bring a charge of unfit to drive through drink or drugs without an evidential breath or blood sample, if they have reasonable grounds to believe that drink or drugs were a factor. The result is exactly the same – a minimum 12 month ban.
In very rare cases people will attempt to run a defence that they would have had no way of knowing that they were impaired (medical reason etc) but these will set you back thousands of pounds in legal fees, as it requires specialist ‘loophole lawyers’. In fact, these defences often backfire as they almost never succeed and they have the effect of irritating the sentencing magistrates who may impose a longer ban than might have otherwise been the case with a guilty plea (as with fines, driving bans are within bands and magistrates have leeway on where to place the ban within a band). You also need to plead ‘not guilty’ to run that defence, which loses you the one third discount on any fine for a guilty plea and will also result in higher surcharges (40% of fine) and higher court costs (£85 guilty plea, rises to at least £775 for a not guilty plea if subsequently found guilty).
Rather than relying on what companies that are selling these products say, people may wish to look at the Sentencing Guidelines published by the sentencing council. These are what Judges and Magistrates use and are publicly available. Here’s just one of the ones that relates to drug driving (there are several).
