Certiorari, Mandamus & Prohibition: The Remedies Explained

Judicial review speaks Latin at exactly the moment applicants can least afford confusion. The remedies are simpler than their names: quash it, compel it, stop it, declare it, hold everything while we decide. Here is each one, and the strategy that goes with it.

Certiorari: Quash It

The workhorse. Certiorari removes the unlawful decision from the legal landscape as if it had not been made — and the matter ordinarily goes back to the decision-maker for lawful re-determination. Understanding that loop is essential expectation-setting: the prize is usually a fair second decision, not a substituted outcome. Under the 2024 planning regime, the courts’ remittal powers are made express, allowing targeted correction instead of wholesale quashing.

Mandamus: Compel It

Where a body is under a duty to act — classically, to decide an application — and simply does not, mandamus compels performance. It is the remedy for the file that has sat in a department for years, the assessment never scheduled, the review never concluded. In practice the mere credible threat of mandamus, delivered in a pre-action letter, produces a striking number of long-awaited decisions.

Prohibition: Stop It

Prohibition restrains a body from acting outside its jurisdiction before the damage is done — the classic modern example being an order prohibiting a criminal trial where blameworthy prosecutorial delay has made a fair trial impossible. It is certiorari’s forward-looking sibling.

Declarations: Say What the Law Is

A declaration authoritatively states the legal position — that a policy is unlawful, that a statutory provision means X, that a practice breaches fair procedures. Public bodies comply with declarations, and a well-aimed one can correct not just your decision but the systemic practice behind it.

Injunctions and Stays: Hold Everything

The remedies that keep cases alive. A stay suspends the challenged decision; an interim injunction restrains action — removal, demolition, revocation — until the hearing. Where irreversible harm would land before judgment, interim protection is not an accessory to the case; it is the case. Say so in the first call.

Choosing: The Remedy Is the Strategy

Start from what would actually fix your situation, then work backwards: limbo needs mandamus; a bad decision needs certiorari and a fair re-run; imminent harm needs interim relief today and everything else after. That analysis happens at the first consultation, alongside the time limit and the grounds.