THE EEC TREATY
9 ACCORDING TO THE FIRST PARAGRAPH OF ARTICLE 119 THE MEMBER STATES ARE OBLIGED TO ENSURE AND MAINTAIN ' ' THE APPLICATION OF THE PRINCIPLE THAT MEN AND WOMEN SHOULD RECEIVE EQUAL PAY FOR EQUAL WORK ' ' .
10 AS THE COURT INDICATED IN THE DEFRENNE JUDGMENT OF 8 APRIL 1976 , THAT PROVISION APPLIES DIRECTLY , AND WITHOUT THE NEED FOR MORE DETAILED IMPLEMENTING MEASURES ON THE PART OF THE COMMUNITY OR THE MEMBER STATES , TO ALL FORMS OF DIRECT AND OVERT DISCRIMINATION WHICH MAY BE IDENTIFIED SOLELY WITH THE AID OF THE CRITERIA OF EQUAL WORK AND EQUAL PAY REFERRED TO BY THE ARTICLE IN QUESTION . AMONG THE FORMS OF DISCRIMINATION WHICH MAY BE THUS JUDICIALLY IDENTIFIED , THE COURT MENTIONED IN PARTICULAR CASES WHERE MEN AND WOMEN RECEIVE UNEQUAL PAY FOR EQUAL WORK CARRIED OUT IN THE SAME ESTABLISHMENT OR SERVICE .
11 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 . THE SCOPE OF THAT CONCEPT , WHICH IS ENTIRELY QUALITATIVE IN CHARACTER IN THAT IT IS EXCLUSIVELY CONCERNED WITH THE NATURE OF THE SERVICES IN QUESTION , MAY NOT BE RESTRICTED BY THE INTRODUCTION OF A REQUIREMENT OF CONTEMPORANEITY .
12 IT MUST BE ACKNOWLEDGED , HOWEVER , THAT , AS THE EMPLOYMENT APPEAL TRIBUNAL PROPERLY RECOGNIZED , IT CANNOT BE RULED OUT THAT A DIFFERENCE IN PAY BETWEEN TWO WORKERS OCCUPYING THE SAME POST BUT AT DIFFERENT PERIODS IN TIME MAY BE EXPLAINED BY THE OPERATION OF FACTORS WHICH ARE UNCONNECTED WITH ANY DISCRIMINATION ON GROUNDS OF SEX . THAT IS A QUESTION OF FACT WHICH IT IS FOR THE COURT OR TRIBUNAL TO DECIDE .
13 THUS THE ANSWER TO THE FIRST QUESTION SHOULD BE THAT THE PRINCIPLE THAT MEN AND WOMEN SHOULD RECEIVE EQUAL PAY FOR EQUAL WORK , ENSHRINED IN ARTICLE 119 OF THE EEC TREATY , IS NOT CONFINED TO SITUATIONS IN WHICH MEN AND WOMEN ARE CONTEMPORANEOUSLY DOING EQUAL WORK FOR THE SAME EMPLOYER .
14 THE SECOND QUESTION PUT BY THE COURT OF APPEAL AND EXPRESSED IN TERMS OF ALTERNATIVES CONCERNS THE FRAMEWORK WITHIN WHICH THE EXISTENCE OF POSSIBLE DISCRIMINATION IN PAY MAY BE ESTABLISHED . THIS QUESTION IS INTENDED TO ENABLE THE COURT TO RULE UPON A SUBMISSION MADE BY THE RESPONDENT IN THE MAIN ACTION AND DEVELOPED BY HER BEFORE THE COURT OF JUSTICE TO THE EFFECT THAT A WOMAN MAY CLAIM NOT ONLY THE SALARY RECEIVED BY A MAN WHO PREVIOUSLY DID THE SAME WORK FOR HER EMPLOYER BUT ALSO , MORE GENERALLY , THE SALARY TO WHICH SHE WOULD BE ENTITLED WERE SHE A MAN , EVEN IN THE ABSENCE OF ANY MAN WHO WAS CONCURRENTLY PERFORMING , OR HAD PREVIOUSLY PERFORMED , SIMILAR WORK . THE RESPONDENT IN THE MAIN ACTION DEFINED THIS TERM OF COMPARISON BY REFERENCE TO