Planning Conditions on Retrospective Permissions: What Applicants Need to Know

When a development has already taken place without permission—whether intentionally or by accident—the planning system doesn’t simply wash its hands of the matter. Instead, the Town and Country Planning Act 1990 allows for retrospective applications, and in enforcement appeals, the Inspectorate can also grant permission after the fact.

But one area that often surprises applicants is the use of planning conditions on retrospective permissions. Many assume that because a building or use is already in place, conditions can’t—or won’t—be imposed. In reality, conditions remain a crucial tool for making unauthorised development acceptable.

Below, we break down how and why conditions are used on retrospective permissions, and what applicants should expect.

Can conditions be imposed on a retrospective permission?

Yes. Whether the retrospective request comes through:

• a standard appeal under section 78,

• a direct retrospective application under section 73A, or

• an enforcement appeal under sections 174 and 177,

…the decision-maker can still impose conditions in the same way as for any other permission.

However, some standard conditions don’t make sense once the development already exists. For example:

• A normal “commencement” condition is irrelevant.

• Conditions requiring something to happen before development begins need rethinking.

Why retrospective conditions must be drafted differently

Many standard conditions assume the development has not yet started—such as requiring approval of materials or submission of a landscaping scheme before work begins. For a retrospective permission, this is obviously impossible.

To keep such conditions enforceable, the Inspectorate uses adapted wording that:

1. Sets a clear timeframe for the applicant to submit, approve, and/or implement the outstanding details; and

2. Includes a specific consequence if the applicant fails to comply.

This “sanction” is what gives the condition enforceability.

What is the ‘sanction’ and how does it work?

In both simple and complex retrospective conditions, the sanction usually means:

• If permission relates to a use → the use must stop if the required actions aren’t completed on time.

• If permission relates to a building or operational development → the works must be removed if the timetable isn’t met.

This doesn’t give the authority power to re-enforce against the original breach (because permission has technically been granted), but it does give them the ability to enforce the condition itself. And in practical terms, the sanction is serious: if breached, the applicant loses the benefit of the permission.

Are less severe sanctions possible?

Sometimes, yes. If the outstanding matter doesn’t fundamentally affect the acceptability of the development, a proportionate approach may involve:

• requiring the action by a certain date without tying it to cessation or demolition; and

• relying on the council's enforcement powers under sections 172 or 187A if the action isn’t carried out.

This still protects the local authority’s position without imposing the nuclear option.

Why the condition’s justification matters

When imposing these model retrospective conditions, decision-makers are expected to explain:

• Why the extra details are needed to make the development acceptable, and

• How the condition will operate, including the consequences of non-compliance.

This transparency is important because retrospective conditions sit outside the usual “prior-to-commencement” logic—so the reasoning needs to be absolutely clear.

Is the timeframe reasonable?

Timeframes must be:

• realistic for the applicant,

• proportionate to the complexity of the required details, and

• appropriate to the degree of harm that would result if they are not submitted.

For complex matters—such as structural details, heritage mitigation, or ecological surveys—planners may allow longer periods. Simpler matters, such as a materials schedule, may justify a shorter window.

Key Takeaways for Applicants

• Retrospective permission is not “condition-free”. Expect conditions where further detail is needed to make the development acceptable.

• Timetables are strict. Failing to meet them can effectively void the permission.

• Be proactive. If required to submit further details, do so early and keep clear records.

• Seek advice. Retrospective conditions can be technical, and poorly handled compliance can lead to costly enforcement action.

About Me

Andrew Ransome is the planning director at ADP and is a chartered member of the RTPI, with over 22 years of town planning experience.

Andrew has extensive experience offering strategic planning solutions to challenging projects in both rural and urban settings. Follow him on Linkedin.

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