15 At the hearing, the United Kingdom argued that the statutory redundancy payment fell outside the scope of Article 119 of the Treaty because it constituted a social security benefit and not a form of pay.
22 It must be pointed out in that regard that, in its judgment of 25 May 1971 in Case 80/70 Defrenne v Belgium (1971) ECR 445, paragraphs 7 and 8, the Court stated that consideration in the nature of social security benefits is not in principle alien to the concept of pay.
However, the Court pointed out that this concept, as defined in Article 119, cannot encompass social security schemes or benefits, in particular retirement pensions, directly governed by legislation without any element of agreement within the undertaking or the occupational branch concerned, which are compulsorily applicable to general categories of workers.
In its judgment of 13 May 1986 in Case 170/84 Bilka-Kaufhaus v Weber von Hartz (1986) ECR 1607, the Court held that the benefits awarded under a supplementary pension scheme fell within the concept of pay, within the meaning of Article 119.
30 The answer to the second question submitted by the Court of Appeal must therefore be that a pension paid under a contracted-out private occupational scheme falls within the scope of Article 119 of the Treaty.
Secondly, the Court of Appeal wishes to ascertain, in substance, whether equal pay must be ensured at the level of each element of remuneration or only on the basis of a comprehensive assessment of the consideration paid to workers.
32 In the case of the first of those two questions thus formulated, it is sufficient to point out that Article 119 prohibits any discrimination with regard to pay as between men and women, whatever the system which gives rise to such inequality.
33 As regards the second of those questions, it is appropriate to refer to the judgments of 30 June 1988 in Case 318/86 Commission v France (1988) ECR 3559, paragraph 27 and of 17 October 1989 in Case 109/88 Handels-og Kontorfunktionaerernes Forbund i Danmark v Dansk Arbejdsgiverforening, acting on behalf of Danfoss (1989) ECR 3199, paragraph 12, in which the Court emphasized the fundamental importance of transparency and, in particular, of the possibility of a review by the national courts, in order to prevent and, if necessary, eliminate any discrimination based on sex.
34 With regard to the means of verifying compliance with the principle of equal pay, it must be stated that if the national courts were under an obligation to make an assessment and a comparison of all the various types of consideration granted, according to the circumstances, to men and women, judicial review would be difficult and the effectiveness of Article 119 would be diminished as a result .