The Supreme Court has reserved its decision on an unprecedented appeal by Facebook, aimed at stopping a referral to the Court of Justice of the European Union about the validity of EU-US data transfer channels.
Chief Justice Mr Justice Frank Clarke said the court would consider what to do next and inform the parties.
The High Court referred the case to the European court in October last year and said the Data Protection Commissioner had "well founded" concerns about whether or not US law provided adequate protections for EU citizens' data privacy rights.
The decision was given in proceedings brought by the Data Protection Commissioner following complaints by Austrian lawyer Max Schrems that the transfer of his personal data by Facebook to the US breached his data privacy rights as an EU citizen.
Ms Justice Caroline Costello referred 11 issues to the CJEU. They raise significant issues of EU law including whether the High Court was correct in finding there was mass, indiscriminate processing of data by US government agencies.
Facebook says the High Court failed to have regard to the 'Privacy Shield' decision under which the European Commission had approved the use of certain EU-US data transfer channels.
It says it's concerned the Court of Justice could make its decisions on foot of the High Court's views relating to US law.
One of the issues the court will have to determine is whether there is actually any entitlement to appeal a reference to the CJEU.