“Parliament has laid down a statutory limit of alcohol in the blood, 80 [mg] per 100 [ml] of blood, no more, no less. At the same time it has laid down a mandatory penalty of disqualification. Just as the amount of the excess cannot affect the issue of guilt or innocence so also it is of no consequence in regard to disqualification. As has already been said, there may be facts which constitute special reasons, but the amount of the excess is not one of them…a special reason must be something other than the commission of the offence itself. This conclusion is strengthened by a consideration of what might be involved if the amount of the excess was held to be a special reason. In the three appeals now before the court the excess amounts were respectively 16, two and 28 [mg], which indicates plainly enough the variation in ideas that would result. Unless the line is drawn with certainty, it would be almost impossible to achieve any uniformity in practice and courts would be exercising a dispensing power which the Act does not confer upon them. One possibility which was canvassed in argument was the application of what is commonly called the “de minimis” principle, particularly in relation to Last’s case, in which the amount of excess was only two [mg]. If in any case the amount of the excess is truly minimal, *216 this would, we hope, provide a good reason for not prosecuting the offender, but once the matter comes before the court, there is no room in this class of case for the principle of “de minimis.”