The Supreme Court has agreed to hear an appeal by Facebook over a High Court decision to refer to the European Court of Justice issues about the transfer of data from the European Union to the United States.

The five judge court said it would hear the unprecedented appeal as a matter of urgency before the end of this year.

Ms Justice Caroline Costello directed a referral of the issues to the EU Court of Justice last May, which concern the validity of European Commission decisions approving certain data transfer channels known as Standard Contractual Clauses.

The questions referred by the High Court raise significant issues of EU law and have major implications.

They include whether or not the High Court was correct to find there was 'mass indiscriminate processing' of data by US government agencies.

Among the grounds of appeal is whether or not there is any entitlement to appeal a High Court decision to refer a matter to the European court.