How long do I have to apply for judicial review?

Short answer

Promptly, and in any event within three months of the decision — reduced to 30 days for planning and procurement challenges. You must also send a Pre-Action Protocol letter at least 14 days before issuing, so in practice you have far less than three months to prepare.

Judicial review is the High Court's power to test the lawfulness of a public body's decision — not whether the decision was wise or fair in an everyday sense. The time limit under CPR Part 54 is strict: promptly, and within three months of the decision being challenged. Planning and procurement challenges are shorter still, at 30 days. Late claims are rarely admitted, and "I was waiting for the complaint to finish" is not usually a good enough reason.

What has to happen inside that window

Pre-Action Protocol letter — sent at least 14 days before issuing, setting out the proposed claim and asking the body to reconsider. It has 14 days to reply.
Claim form N461 — filed at the Administrative Court with detailed grounds, a witness statement and the documents relied on.
Acknowledgement of service — the defendant has 21 days to file summary grounds.
Permission — a judge decides on the papers whether the claim is arguable, usually within 6 to 12 weeks. Roughly a quarter to two-fifths of applications get through.
Substantive hearing — 4 to 9 months after permission, lasting one to three days, with judgment usually reserved. Expect 9 to 18 months end to end.

Genuinely urgent cases — a removal in hours, an eviction in days — can be expedited with an application for interim relief, and that should be made immediately rather than waiting for the protocol period to run.

Before you commit

Judicial review is a remedy of last resort. If a statutory appeal, tribunal or ombudsman route exists, the court will normally expect you to use it — which is why benefits decisions go through mandatory reconsideration and tribunal, and employment disputes to the Employment Tribunal. The grounds are illegality, irrationality and procedural unfairness, with human rights, the public sector equality duty and legitimate expectation as related routes.

Cost is the other constraint. Your own legal costs on a typical case run from £15,000 to £60,000 or more, and losing normally means paying the other side's. Exposure can be limited by a costs capping order in public interest cases, and environmental claims under the Aarhus Convention are capped at £5,000 for individuals and £10,000 for organisations. Legal aid remains available for housing and homelessness, immigration and asylum, mental health detention and community care. Winning usually means the decision is quashed and retaken lawfully — not that you get the outcome you wanted, and rarely any damages.

Read the full guide: Judicial Review: When and How to Use ItCovers eligibility, the process, deadlines, and next steps in depth.

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