O'Brien and others v Ministry of Justice and others [2015]

Both of these joined cases involved the right or otherwise to pension benefits and the particular dates from which entitlements might apply. O'Brien was a part-time judge and sought pension entitlements pro-rated with full-time judges. In this particular case, the claimant sought back-dating of pension entitlements to the date he started work (1978) rather than 2000, when the Part Time Workers Directive was transposed into UK law. The Court of Appeal ruled against him - the principle of 'no retro-activity' means that EU laws should not have a retrospective effect; they should apply from the date on which they are required to be law. In his case that was 2000, so earnings before that could