“When Parliament lays down a statutory requirement for the exercise of legal authority it expects its authority to be obeyed down to the minutest detail. But what the courts have to decide in a particular case is the legal consequence of non-compliance on the rights of the subject viewed in the light of a concrete state of facts and a continuing chain of events. It may be that what the courts are faced with is not so much a stark choice of alternatives but a spectrum of possibilities in which one compartment or description fades gradually into another. At one end of this spectrum there may be cases in which a fundamental obligation may have been so outrageously and flagrantly ignored or defied that the subject may safely ignore what has been done and treat it as having no legal consequences upon himself. In such a case if the defaulting authority seeks to rely on its action it may be that the subject is entitled to use the defect in procedure simply as a shield or defence without having taken any positive action of his own.”
“24…the measures imposing penalties permitted under national legislation must not exceed the limits of what is appropriate and necessary in order to attain the objectives legitimately pursued by the legislation in question; when there is a choice between several appropriate measures, recourse must be had to the least onerous, and the disadvantages caused must not be disproportionate to the aims pursued (see, to that effect, Joined Cases C-379/08 and C-380/08 ERG and Others[2010] ECR I-2007 , paragraph 86).”