Not really. We have a problem, as you mentioned, with concentration. We already discussed it. Actually, the effects of different drugs vary so much from one individual to another that we cannot tell what quantity will...
I hope that you will put the same questions to the drug recognition experts when they appear before you. We cannot conclude that if so many parts per million of marijuana or cocaine were detected, it is therefore clear that the person's faculties are impaired because anyone with that level of concentration in their body would have problems.
The quantity could be very high. However, we have no reliable instruments. Moreover, there is no set legal limit like the 80 milligrams per 100 millilitres established for alcohol by the legislation. Therefore, we cannot shut the gate, as you say. We can shut the gate on the "two-beer defence", because we have an instrument that is very accurate, modern, etc., that gives us reliable results and proves that you have exceeded the limit established by Parliament. However, because we have no established limit for drugs, we cannot say that a crime has been committed, because there is no prescribed concentration level.