Rationality and proportionality - judicial review

What is the key issue behind the challenge of irrationality in judicial review?

when a decision is so outrageous in its defiance of logic or accepted moral standards that no sensible decision-maker could have reached it. This ground is intended to flag decisively flawed decisions without the court having to assess the merits as such.

How did Lord Diplock describe irrationality in GCHQ?

Lord Diplock referred to irrationality (or “unreasonableness”) as a decision which is so outrageous in its defiance of logic or accepted moral standards that no sensible person, having applied their mind, could have arrived at it.

What formulation did Lord Greene MR provide in Associated Provincial Picture Houses v Wednesbury Corporation?

He stated that if a decision on a competent matter is so unreasonable that no reasonable authority could ever have made it, then the courts can interfere.

How did Sir Thomas Bingham define the threshold for irrationality in administrative decisions?

Sir Thomas Bingham defined it as a decision which is "beyond the range of responses open to a reasonable decision-maker."

Why is there a high threshold for challenging decisions on the grounds of irrationality?

As judicial review is supervisory—not appellate—and judges are cautious in intervening in the merits of a decision; they require an overwhelming case where the reasoning process is not only deficient but so lacking that it undermines the decision’s logic entirely.

What does the high threshold mean in practice for irrationality challenges?

The threshold means that only decisions that are exceptionally absurd or lacking in logic will be found irrational, as judges avoid engaging in mere disagreements over the merits of the decision and reserve intervention for cases of overwhelming defect.

What is meant by the “Super-Wednesbury” approach, and when is it applied?

where the threshold is raised even further, particularly when political and economic considerations are at stake. In such situations (e.g. Nottinghamshire CC v Environment Secretary, R v (Environment Secretary) Hammersmith & Fulham [1990]), courts are reluctant to assess rationality against statutory powers that Congress or Parliament has allocated to ministers.

How is the threshold for irrationality adjusted in human rights cases?

The standard is flexed downward, employing “anxious scrutiny.” When a decision potentially affects a fundamental right—such as the right to life—the court demands a higher degree of justification before finding the decision reasonable.

What did Lord Bridge and Sir Thomas Bingham say regarding the scrutiny of decisions affecting human rights?

Lord Bridge observed that an administrative decision potentially putting a life at risk demands the most anxious scrutiny. Sir Thomas Bingham added that the greater the substantial interference with human rights, the more the court requires justification before it can find the decision reasonable.

In the case of K v SSHD [2023], how was irrationality demonstrated?

Mrs K’s case showed that the Home Secretary’s reasoning was so flawed—lacking logical process and failing to address crucial considerations—that the decision was deemed irrational. The challenge also raised issues of detrimental reliance and legitimate expectations, though the irrationality ground focused on the deficient reasoning process.

What is the principle of proportionality in administrative law?

Proportionality involves balancing the interference with a fundamental right against the achievement of a legitimate public policy objective. It requires assessing whether the legislative objective justifies the limitation of a right and ensuring that the measure is strictly necessary to achieve that objective.

What key questions must a decision-maker ask under the principle of proportionality?

• Is the legislative objective sufficiently important to justify limiting a fundamental right?

• Does the decision limit the right by no more than is strictly necessary?

• Is the decision designed to effectively give effect to the legislative objective?

How does proportionality differ from the rationality (Wednesbury) test?

Unlike the rationality test—which asks if a decision is within the range of reasonable responses—proportionality requires the court to assess the precise balance struck between the limitation of a right and the public policy goal, making it a more robust scrutiny of rights interference.

Where is the principle of proportionality routinely applied, and how has it influenced UK law?

applied by international courts under the European Convention on Human Rights (ECHR) and by the Court of Justice of the European Union (CJEU). In the UK, it is applied when considering Convention rights under the Human Rights Act.

What is the current stance of English law on proportionality according to Lord Sumption’s observations?

English law has not formally embraced a fully structured proportionality test; however, over the past three decades it has moved towards recognising a concept that closely resembles proportionality, influenced by European jurisprudence in areas beyond the traditional human rights and EU law domains

How do judicial prudence and deference manifest in the context of proportionality challenges?

Courts remain cautious in applying a fully interventionist proportionality analysis because a lower threshold might lead to excessive judicial intrusiveness. Thus, while proportionality offers a more detailed framework for rights protection, courts balance its application against the need to respect enshrined legislative and executive expertise.

What future development might be anticipated regarding the principle of proportionality in administrative law?

There is the possibility that further case-by-case developments could expand the grounds for review by explicitly incorporating proportionality, especially as the courts continue to refine their approach to balancing public policy and individual rights. Lord Diplock’s remarks hint at this evolving direction.

How have judges informally incorporated proportionality into their reasoning despite its not being universally endorsed?

Judges have sometimes included elements of proportionality—balancing rights and public policy—even without adopting it as a formal, structured test. Examples cited in cases such as Leech [1994] and Daly [2001] show that proportional reasoning is already influencing judicial assessments, even as debates continue over its formal adoption