Supreme Court: Expert evidence not generally necessary in judicial review challenges to proportionality of legislation

Supreme Court: Expert evidence not generally necessary in judicial review challenges to proportionality of legislation

The Supreme Court has dismissed an appeal by Gemma O’Doherty and John Waters in their failed challenge to the Covid-19 lockdown restrictions from Spring 2020. The appeal concerned whether the applicants were required to show expert evidence relating to the proportionality of the measures adopted by the government and the effect on constitutional rights.

Delivering judgment in the case, Chief Justice Donal O’Donnell held that expert evidence was generally not essential to challenge the constitutional validity of a legislative provision and there was no principle that the onus of justifying a legislative measure lay upon the State. However, in certain circumstances, it may be necessary to adduce evidence and this depended on the nature of the challenge to the legislation.

Since the applicants advanced a case that the lockdown measures were an international conspiracy, they were challenging the State’s assessment of the public health situation. They were therefore required to adduce plausible evidence in order to reach the threshold of arguability, but they failed to do so.


The relevant background to the appeal can be found in this previous case report in the Court of Appeal decision. In summary, the applicants issued judicial review proceedings in March 2020 seeking to challenge the emergency lockdown measures which were put in place by the Government in response to the Covid-19 pandemic. The challenge was wide-ranging and made farfetched allegations relating to the pandemic being an international conspiracy.

The applicants failed in their application for leave to bring the judicial review proceedings in the High Court, where Mr Justice Charles Meenan determined that there was nothing in the emergency legislation which was repugnant to the Constitution. As part of the ruling, it was determined that the applicants had failed to reach the threshold of arguability in G. v. DPP [1994] 1 I.R. 374.

In particular, it was held that the applicants had to put on affidavit some facts which, if proven true, would support a view that the measures were disproportionate and unconstitutional. The High Court decision was upheld by the Court of Appeal.

Subsequently, the applicants were granted leave to appeal on only one ground to the Supreme Court. The question which was asked was whether leave for judicial review should have been granted in circumstances where the applicants failed to lay an evidential foundation by way of scientific or medical reports regarding the proportionality of the legislative measures.

This ground raised two further points in the case which were: “are the Measures on their face of such clear and significant impact upon the constitutional rights of every citizen that if their validity is challenged in judicial review proceedings leave to seek judicial review should be granted?” If the answer to this question was “yes”, it was asked whether the evidential burden shifted to the State to demonstrate the necessity and proportionality of the measures, even if the applicants had not advanced any evidence of impact on any person.

Supreme Court

Giving the leading judgment, Chief Justice Donal O’Donnell began by considering the place for evidence in constitutional challenges. It was noted that it had not historically been the case that “more by way of evidence addressing what might be described as the substance of the challenge, or the policy and objectives of the measure in question is required, or still less essential.” As a general rule, expert evidence on the merits or substance of a provision was not an essential feature of a constitutional challenge to the validity of legislation, the court held (Norris v. The Attorney General [1984] I.R. 36).

The task of a court in considering a constitutional challenge was to “place the challenged statute against the Constitution as it has been interpreted and by a process of logical analysis come to a determination”. While this might require evidence of the operation or background to the statute, it could not be said that evidence was “an essential element of the task” of interpretation.


The court then considered the issue of proportionality and the burden of proof. The court did not accept that the onus of proof should shift onto the State party which was defending the constitutionality of legislation, noting that the Oireachtas was not an evidence-gathering body and there was no requirement to obtain evidence before enacting provisions in the public interest.

There would be a perceptible shift in the separation of powers if a court could “conclude that the judgment of the Oireachtas is not sufficient because of the view a trial judge takes of whatever expert or other evidence has been adduced in a particular piece of litigation controlled by the parties”. Further, an onus-shifting approach was not consistent with the presumption of constitutionality of legislation, the court held.

The court turned to consider whether the applicants met the threshold of the G v. DPP standard of arguability. It was noted that the High Court determined that the applicants did not meet this standard due to an evidential deficit. It was held that the High Court and Court of Appeal were incorrect to hold that evidence as to policy (going beyond standing to sue or impact on constitutional rights) was essential to challenge the validity of the legislation. In reality, the proposition was more complex and appropriate position depended on the nature of the challenge.

Insofar as the applicants brought a global challenge for the basis of the Acts and Regulations which underpinned the lockdown, the applicants were required to provide some plausible foundation in evidence. This was because: “The claim was not simply that the legislation constituted a disproportionate interference with constitutional rights, it was that it was unconstitutional because it was the product of a conspiracy.” However, no such evidence was provided.

While the applicants undoubtedly contended in their challenge that the measures were disproportionate, the claim involved a challenge to the State’s assessment of the public health situation. Again, plausible evidence was required “that would be capable of making an arguable case that the State’s assessment was beyond any permissible view of the relevant situation”.

As such, even the limited claim of lack of proportionality did not reach the threshold of arguability. The court also rejected the reasoning of Mr Justice Gerard Hogan, who would have granted leave on some limited grounds based on the applicant’s statement of grounds. It was determined that Mr Justice Hogan was performing “radical surgery” on the applicants’ case and that he would have been granting leave on bases that were fundamentally different from the case made.


The court concluded that expert evidence was not essential to challenge the constitutional validity or proportionality of legislation. There was no principle that the onus of justifying a legislative measure shifted onto the State when there was proof of interference with rights.

Further, it was possible to advance a claim of proportionality while accepting the objective of the legislation and the State’s assessment of the circumstances giving rise to the legislation. However, if a challenge involved a dispute on the underlying assessment, then plausible evidence was required to set out an arguable case.

The applicants failed to adduce sufficient evidence in their constitutional challenge to the legislation.

O’Doherty and Anor. v. The Minister for Health and Ors. [2022] IESC 32

Share icon
Share this article: