MADE AVAILABLE TO THE MEMBER STATES BY THAT PROVISION IS POSSIBLE ONLY AS REGARDS THE FUTURE .
21 ON THE CONTRARY , IT FOLLOWS FROM THE SPIRIT AND SCHEME OF ARTICLE 17 THAT AN AGREEMENT WITHIN THE MEANING OF THAT PROVISION MUST ALSO BE CAPABLE , IN THE INTERESTS OF THE WORKER OR WORKERS CONCERNED , OF COVERING PAST PERIODS . SINCE ARTICLE 17 PROVIDES FOR AN EXCEPTION INTENDED TO MITIGATE THE DIFFICULTIES RESULTING FROM THE APPLICATION OF ARTICLES 13 TO 16 TO SPECIAL SITUATIONS NOT SPECIFICALLY ENVISAGED IN REGULATION NO 1408/71 , IT MAY BE USED NOT ONLY TO ENSURE THAT A CERTAIN SITUATION DOES NOT ARISE BUT ALSO TO REMEDY AN EXISTING SITUATION THE INJUSTICE OF WHICH APPEARS ONLY AFTER IT HAS ARISEN .
22 IT MUST ALSO BE EMPHASIZED THAT , IN VIEW OF THE TIME NEEDED FOR TWO OR MORE MEMBER STATES TO REACH AGREEMENT AS TO WHETHER IT IS APPROPRIATE TO DEROGATE FROM ARTICLES 13 TO 16 , ARTICLE 17 WOULD BE DEPRIVED OF MUCH OF ITS MEANING IF THE AGREEMENT COULD HAVE ONLY PROSPECTIVE EFFECT .
23 IT MUST THEREFORE BE CONCLUDED THAT AN AGREEMENT ENTERED INTO BETWEEN TWO OR MORE MEMBER STATES PURSUANT TO ARTICLE 17 OF REGULATION NO 1408/71 MAY DECLARE LEGISLATION OTHER THAN THAT DESIGNATED IN ARTICLES 13 TO 16 APPLICABLE IN RESPECT OF PAST PERIODS PROVIDED , OF COURSE , THAT THE AGREEMENT IS IN THE INTERESTS OF THE WORKER OR WORKERS IN QUESTION .
24 IN ITS OBSERVATIONS SUBMITTED TO THE COURT THE RAAD VAN ARBEID MAINTAINS THAT MEMBER STATES MAY NOT AVAIL THEMSELVES OF THEIR RIGHT TO DEROGATE FROM ARTICLES 13 TO 16 IN A CASE SUCH AS THIS WHERE THE WORKER IN QUESTION HAS FAILED TO AFFILIATE HIMSELF TO THE SOCIAL SECURITY SCHEME DESIGNATED IN ARTICLE 13 ( 2 ) ( A ).
25 NO SUCH RESTRICTION ON THE POWER CONFERRED UPON THE MEMBER STATES APPEARS ANYWHERE IN ARTICLE 17 . ON THE CONTRARY , THAT PROVISION MAKES NO REFERENCE TO THE REASONS OR CIRCUMSTANCES WHICH MIGHT LEAD THE MEMBER STATES TO DEROGATE FROM ARTICLES 13 TO 16 . IT FOLLOWS THAT , IN THAT RESPECT , THE MEMBER STATES ENJOY A WIDE DISCRETION TO WHICH THE ONLY LIMITATION IS REGARD FOR THE INTERESTS OF THE WORKER .
26 CONSEQUENTLY THE REPLY TO THE FIRST QUESTION MUST BE THAT ARTICLE 17 OF REGULATION NO 1408/71 MAKES IT POSSIBLE FOR TWO MEMBER STATES , IN THE CASE OF A WORKER WHO FOR A LARGE NUMBER OF YEARS HAS NOT BEEN AFFILIATED TO THE SCHEME OF ONE OF THOSE MEMBER STATES WHICH WAS APPLICABLE TO HIM PURSUANT TO ARTICLES 13 TO 16 INCLUSIVE OF THE SAID REGULATION , BY AGREEMENT TO DECLARE APPLICABLE , IN RESPECT OF THOSE YEARS , THE LEGISLATION OF THE OTHER MEMBER STATE PROVIDED THAT SUCH AGREEMENT CORRESPONDS TO THE INTERESTS OF THE WORKER CONCERNED .
THE SECOND QUESTION
27 THE CENTRALE RAAD VAN BEROEP ' S SECOND QUESTION SEEKS TO ASCERTAIN WHETHER A WORKER