Factortame (Case C-213/89 [1990] ECR I-2433, starting in 1988, ff.) was the case that Eurosceptics felt doomed UK parliamentary sovereignty. Factortame said that, having committed itself to the treaty, a Member State could not then contradict the treaty with contrary domestic action. Specifically, no discrimination against nationality (now TFEU Art. 18) has been permitted since the beginning. Nevertheless, parliament amended the Merchant Shipping Act in 1988 to prevent Spanish fishermen from catching fish in UK waters by requiring, for example, that 75% of the shares in a fishing enterprise must owned by people domiciled and residing in UK. The diehards never accepted that parliament had to exercise its authority within the framework established by the treaty.