April 1st is the line in the sand — but where exactly is the line drawn?

With only days to go until the Planning Inspectorate (PINS) launches its most significant procedural overhaul in a decade, a single question is dominating our inbox: "I'm submitting an appeal on April 2nd — do I have to follow the new rules?"

The answer depends entirely on a date you likely set months ago.

The rule of thumb

According to Section 1.3 of the new Procedural Guide (published February 2026), the new rules apply to any appeal resulting from a planning application submitted to the Local Authority on or after 1 April 2026.

If your LPA validation date is 31 March 2026 or earlier, the new Part 1 restrictions (like the Evidence Lock) do not apply to you. You follow the legacy procedural guide.

This means the "Submit Once, Submit Right" era is determined by the date your project first hit the LPA portal — not the date you received your refusal, or the date you filed your appeal. We've linked to the guidance at the bottom of this article so you can check.

The "two-tier" system for 2026

For the remainder of this year, the industry will effectively be operating under two different sets of rules. It is vital you know which tier your project sits in:

| Application submitted | Rules that apply | What that means | |---|---|---| | On or before 31 March 2026 | The old guidance | You can still submit a full Statement of Case and potentially evolve evidence. | | On or after 1 April 2026 | The new guidance | Part 1 Written Reps: no Statement of Case, no new evidence, strict Evidence Lock. |

Why the application date matters so much

PINS has chosen the application date as the trigger to ensure procedural fairness. Under the new rules, you will only be able to front-load your evidence within the original planning application. If you submitted an application in January 2026, you didn't know you needed to provide that level of appeal-ready detail. PINS will therefore allow those older cases to use the traditional appeal process (the Part 2 procedure).

However, for any project starting from this Wednesday, there is no grace period.

Part 1 vs. Part 2 procedures

The "Part 1" and "Part 2" labels refer to the Written Representations procedure. Most confusion stems from which path a case takes.

Part 1 — the "expedited" route (Section 9.1.3)

This applies to most standard refusals (Householder, Minor Commercial, Advertisements, etc.).

• Key constraint: You generally cannot submit new evidence or a separate Statement of Case (Section 7.3.1).

Part 2 — the "standard" route (Section 9.1.5)

This is reserved for cases that don't fit the expedited type, specifically:

• Non-determination cases (where the LPA failed to decide on time).
• Listed Building Consent appeals.
• Discontinuance Notices.

Summary

If you are filing an appeal today for an application made in January or February 2026, you should refer to the pre-April 2026 Procedural Guide. You still have the right to submit a Statement of Case and your evidence is not locked to the original application file in the same way the new Part 1 rules dictate.

The most important takeaway: if you are starting a new project this week (1 April 2026 onwards), the safety net is gone. You must front-load every argument into the initial application because the Part 1 procedure will not let you top up your case later.

The trap: non-determination cases

If you are appealing against non-determination for an application submitted in March, you are safe under the old rules. But if you withdraw that application and resubmit on 2 April to tweak the design, you have officially stepped into the new regime. You are now subject to the Evidence Lock, along with the AI disclosure mandates.

Our advice: check your "valid date"

Don't guess. Check the Validation Letter from your Local Planning Authority.

• If that letter confirms a valid date of 1 April 2026 or later, your project is now in the high-stakes zone.
• You must ensure your Planning Statement is appeal-proof from Day 1. You will have the usual 6 weeks during the consultation phase to add information to any application.
• There may be advantages to appealing a case before 1 April depending on your circumstances, but in many cases if you made an application before this date you will be assessed under the new rules.

At planningappeals.co.uk, we provide links and tools to look at how Inspectors are interpreting policy. Our insights and intelligence sections of the website are expanding and we can provide bespoke searches to specific questions. We are keen to continue building a tool that is genuinely useful for those in the industry. If you want to see a feature or tool, please do reach out.

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Don't apply 2025 thinking to a 2026 application. Strengthen your argument today.

New PINS procedural guidance for applications dated on or after 1 April 2026: https://www.gov.uk/guidance/planning-appeals-procedural-guide-for-appeals-relating-to-applications-dated-on-or-after-1-april-2026#introduction

Old procedural guidance (for applications submitted on or before 31 March 2026): https://www.gov.uk/government/publications/planning-appeals-procedural-guide