Britain’s Supreme Court on Tuesday rejected a last-ditch bid by the British government to stop Europe’s top court from considering a case which seeks to determine whether London can unilaterally reverse Brexit.

Scottish politicians who are opposed to Britain exiting the European Union want the European Court of Justice (ECJ) to clarify whether London can withdraw its notification to leave without permission from the EU’s other member states.

Pro-EU supporters who want a second referendum are hoping the case will give the option that Britain could change its mind in a second referendum and remain in the bloc after all.

The ECJ is due to hear the case on Nov. 27.

The government had argued that whether or not Britain could reverse the decision was immaterial since ministers had no intention of doing so.

The anti-Brexit petitioners are hoping the ECJ will rule that Britain has a legal unilateral option of staying in the EU, the world’s biggest trading bloc, once the final outcome of divorce negotiations are known.

Last week, May concluded a withdrawal agreement with the EU but many in her own party along with the small Northern Irish party which props up her minority government and opposition lawmakers have said they will oppose it.

She has said the country faces three options: backing her deal, leaving the EU in a disorderly “no deal” Brexit, which would be very disruptive for businesses and citizens, or no Brexit.

It is not clear when the ECJ might issue its ruling to clarify the interpretation of Article 50 of the EU treaty, under which London last year gave two years’ notice of its departure.