In the present case I assume that the United Kingdom intended to fulfil its obligations under art 119.A reference for a preliminary ruling was then made to the ECJ.
The ECJ held that Ms Smith had a claim because she could compare her pay with a former colleague, thus approving Lord Denning MR's dissent on the interpretation of the UK Act.
In such a situation the decisive test lies in establishing whether there is a difference in treatment between a man and a woman performing "equal work" within the meaning of article 119.
It is clear that the latter proposition, which is the subject of question 2(a), is to be classed as indirect and disguised discrimination, the identification of which, as the Court explained in the Defrenne judgment, cited above, implies comparative studies of entire branches of industry and therefore requires, as a prerequisite, the elaboration by the Community and national legislative bodies of criteria of assessment.
From that it follows that, in cases of actual discrimination falling within the scope of the direct application of Article 119, comparisons are confined to parallels which may be drawn on the basis of concrete appraisals of the work actually performed by employees of different sex within the same establishment or service.Lord Denning MR, Lawton LJ and Cumming-Bruce LJ ordered Macarthys to pay costs to fulfil the order of the ECJ.