This principle is contained in the third paragraph of Art 5 of the Treaty on European Union1:
“Under the principle of proportionality, the content and form of Union action shall not exceed what is necessary to achieve the objectives of the Treaties.”
“Union action”, in this context, would appear to mean action by the principal European legislative bodies (see V1.220), and the relevant authorities in individual member states. In practice, the principle has usually been invoked when member states have imposed legislation which prejudices a person's rights under European legislation.
The factors to be taken into account when considering proportionality were enunciated by Lord Hoffman in CR Smith2, where he said that the principle was divided into three sub-principles: “first, a measure must be suitable for the purpose for which the power has been conferred; secondly, it must be necessary in the sense that the purpose could not have been achieved by some other means less burdensome to the persons affected and thirdly, it must be proportionate in the narrower sense, that is, the burdens imposed by the exercise of the power must not be disproportionate to the object to be achieved.”
In Garage Molenheide3, the Belgian authorities invoked legislation which permitted them to retain a refund due to the appellant where doubts existed over the accuracy of returns submitted by the appellant. The ECJ held that if that legislation constituted a bar to effective judicial review, in particular review of the urgency and necessity of retaining the refundable VAT balance, and