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High Court issues guidance on modular trials

27 May 2024 / courts Print

High Court issues guidance on modular trials

The High Court has given guidance on when so-called modular trials can proceed in cases where related proceedings are ongoing before the EU courts, Pinsent Masons lawyers write.

A modular trial is where trial issues are heard and determined at different stages, rather than in a single process.

The High Court ruled that a modular trial should not take place in a dispute between Meta Platforms Ireland Ltd (Meta) and the Irish Data Protection Commission (DPC).

Instead, the High Court said that the Irish proceedings should be put on hold until a related matter was resolved by the Court of Justice of the EU (CJEU).

The Irish proceedings concern a statutory appeal Meta has raised against the DPC over a GDPR enforcement action in respect of its WhatsApp service in 2022.

Parallel proceedings

Meta has also instituted parallel judicial-review proceedings challenging the constitutional validity of the Irish Data Protection Act 2018.

The CJEU proceedings concern the binding decision by the European Data Protection Board (EDPB) in the enforcement action.

Thus, the CJEU decision may lead to an important interpretation of GDPR concerning the lawful imposition of administrative fines.

In the Irish proceedings, both Meta and the DPC were agreed that some aspects of the case before the High Court would need to be deferred until after the CJEU ruling.

They disagreed over whether some aspects of the case should proceed before the High Court, notwithstanding the ongoing CJEU proceedings.

The DPC wanted matters not directly affected by the CJEU outcome to be considered by the High Court in the interim.

It argued that the High Court was obliged under EU law to determine the domestic proceedings expeditiously, and that this was best achieved by a modular trial.

Meta disagreed, however, arguing that the High Court should adjourn the Irish proceedings until there was an outcome from the CJEU, the Pinsent Masons lawyers state.


The High Court decided that there should be an adjournment in the Irish proceedings.

Orla Hubbard of Pinsent Masons said that the High Court set out the criteria for determining whether to direct a modular trial.

Modularisation will not be directed unless the court is satisfied that the separate issues can properly be heard and decided in isolation.

This is the principal determinant of whether to direct a modular trial.

If such separation would cause prejudice to one of the parties, then modularisation would have to be refused, the court found.

In this case, the High Court highlighted the risk that it could interpret the GDPR in a way that was subsequently at odds with EU case law if the CJEU took an alternative view.

Also, adjournment would not give any faster legal effect to the outstanding matters, since both parties agree that they are subject to the CJEU ruling.

The High Court said that the strands of the domestic proceedings could not sensibly be separated out, and that the CJEU ruling was expected shortly.

Fragmented appeals

The High Court also said that a modular trial ran the risk of prolonging proceedings, and fragmented appeals to the Court of Appeal and/or preliminary references to the CJEU.

“This decision also shows that the Irish courts will take a pragmatic approach in managing cases involving issues of interpretation of the GDPR and decisions of the DPC, in order to avoid messy and splintered appeals,” Hubbard said.

“The decision also helpfully sets out criteria which a court may use in determining whether it is appropriate to direct a modular trial,” she added.

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