97. On a number of occasions, the Court has stated its understanding of the phrase “necessary in a democratic society”, the nature of its functions in the examination of issues turning on that phrase and the manner in which it will perform those functions. It suffices here to summarise certain principles:
(a) the adjective “necessary” is not synonymous with “indispensable”, neither has it the flexibility of such expressions as “admissible”, “ordinary”, “useful”, “reasonable” or “desirable” (see the Handyside judgment of 7 December 1976, Series A no. 24, p. 22, § 48);
(b) the Contracting States enjoy a certain but not unlimited margin of appreciation in the matter of the imposition of restrictions, but it is for the Court to give the final ruling on whether they are compatible with the Convention (ibid., p. 23, § 49);
(c) the phrase “necessary in a democratic society” means that, to be compatible with the Convention, the interference must, inter alia, correspond to a “pressing social need” and be “proportionate to the legitimate aim pursued” (ibid., pp. 22-23, §§ 48-49);
(d) those paragraphs of Articles of the Convention which provide for an exception to a right guaranteed are to be narrowly interpreted (see the above-mentioned Klass and others judgment, Series A no. 28, p. 21, § 42).
98. The Court has also held that, in assessing whether an interference with the exercise of the right of a convicted prisoner to respect for his correspondence was “necessary” for one of the aims set out in Article 8 § 2 (art. 8-2), regard has to be paid to the ordinary and reasonable requirements of imprisonment (see the above-mentioned Golder judgment, Series A no. 18, p. 21, § 45). Indeed, the Court recognises that some measure of control over prisoners’ correspondence is called for and is not of itself incompatible with the Convention.
- Proportionality of sentencing