Walkthrough: a scheme amended mid-build
Seven changes arose during construction on an illustrative nine-unit scheme. Four went through section 96A in 24 days; three needed a section 73 and eight weeks.
Changes during construction are normal. The mistake is treating them all the same way. This illustrative walkthrough follows a nine-unit scheme in a market town where seven changes arose between the start on site and first fix, and where four went through a section 96A non material amendment and three needed a section 73 application. The split mattered, because a section 96A application is determined in 28 days and a section 73 takes eight weeks, and the contractor's programme assumed the shorter route for everything.
This is an illustrative example rather than a real case. The procedural points are the ones that recur.
The changes proposed during construction
The permission was for nine dwellings, two terraces and a pair of semis, with an approved plans condition listing eleven drawing numbers, a materials condition, a parking and cycle parking condition and a landscape condition with a five-year replacement clause.
The changes that came forward were:
- Rear elevation windows shifted by 300 mm to suit the internal partition layout, with one additional obscure-glazed bathroom window.
- Substitution of the approved facing brick for a different brick of the same colour range, the approved one having gone out of production.
- Relocation of the communal bin store by four metres, away from a plot boundary.
- Two rooflights becoming three on the rear roof slope of one unit.
- An increase in ridge height of 350 mm across the terrace, needed for a deeper structural zone over the open-plan ground floor.
- Loss of one parking space to accommodate a cycle store that the condition required but the layout had not shown.
- Removal of a category B ash on the northern boundary, which the arboricultural report had recommended retaining and which had since declined.
Seven changes, one project, two statutory routes. The design team's first instinct was to bundle them into a single non material amendment, which would have been refused.
Testing whether they were non material
Section 96A of the Town and Country Planning Act 1990 lets a local planning authority make a non material change to an existing permission. There is no statutory definition of non material, and that is deliberate: the authority judges it in the context of the particular permission and its setting.
The questions the case officer actually asked were practical ones. Would the change have altered the recommendation at the time. Would a neighbour who commented on the original application have had anything new to say. Does the change conflict with the description of development or with the reason any condition was imposed. Does it affect anything the planning balance turned on.
Applying that to the list, four changes came out clearly non material. The window shift of 300 mm on a rear elevation facing the applicant's own land, with an obscure-glazed bathroom window, changed nothing about overlooking. The brick substitution was supported by samples and a letter from the supplier confirming the original was discontinued. The bin store move improved the position relative to the boundary. The third rooflight on a rear slope was invisible from any public vantage point.
The officer also made a point worth recording: a change can be non material in isolation and material in combination. Submitting four small changes together is fine. Submitting four small changes together with a ridge height increase invites a refusal of the whole application.
Which changes needed section 73 instead
Three changes failed the test, for three different reasons.
| Change | Why section 96A was wrong | Route used |
|---|---|---|
| Ridge height up 350 mm | Alters the approved elevations in a way visible from the street and bears on the daylight assessment for the neighbour to the east | Section 73 varying the approved plans condition |
| Parking space lost to cycle store | Directly conflicts with the numerical requirement in the parking condition | Section 73 varying the parking condition, with the revised layout |
| Category B ash removal | Conflicts with the reason for the landscape and arboricultural condition and needs replacement planting agreed | Section 73 varying the landscape condition, supported by an updated arboricultural report |
Section 73 allows the authority to grant permission subject to different conditions, and it can also change the approved plans where the approved plans are secured by condition. What it cannot do is produce a development that conflicts with the description of development on the original permission, a limit established by the Court of Appeal in Finney v Welsh Ministers. Nine dwellings remained nine dwellings, so the description was untouched.
The Levelling-up and Regeneration Act 2023 also inserted a further variation route at section 73B, and its commencement and scope should be checked before it is relied on.
The application and the determination period
The non material amendment went in with a covering statement of two pages, a drawing comparison sheet showing each change as existing-approved against proposed, the brick samples and the supplier letter. The fee for a section 96A application is a modest fixed amount, indexed annually, so the current schedule is worth checking rather than assuming last year's figure.
It was determined in 24 days. No publicity or consultation is required for a section 96A application, which is most of the reason it is faster.
The section 73 application ran the full course: validation, 21 days of neighbour notification, a highways consultation on the parking change, and determination at week seven. The supporting documents were a short planning statement addressing each varied condition, a revised site layout, revised elevations with a comparative daylight note for the neighbour to the east, an updated arboricultural report and a replacement planting plan. The updated Design and Access Statement was short, because only the parts that had changed needed revisiting.
One procedural trap is worth naming. There is no right of appeal against refusal of a section 96A application. If the authority says no, the options are to resubmit differently, go the section 73 route, or challenge by judicial review, which in practice means the section 73 route. That asymmetry is a reason to put borderline changes into a section 73 from the start.
Effect on the approved plans condition
Both routes end up in the same place, which is a revised schedule of approved drawings. Check the decision notice carefully when it arrives.
The section 96A decision listed the superseded drawing numbers and the substituted ones. The section 73 permission was a new permission with a complete condition schedule, re-stating every condition including those already discharged, with its own time limit for implementation. That last point catches people: a section 73 permission carries a fresh set of conditions, so read them against the original rather than assuming they are identical.
The practical housekeeping is to maintain one controlled drawing register showing, for each drawing, the issue approved under the original permission, the issue substituted by amendment, and the date of the decision that did it. Without that, the site is being built from drawings nobody can prove are the approved ones.
Community infrastructure levy is worth a thought too. A section 73 permission can require the charge to be recalculated where floorspace changes, while a section 96A amendment does not create a new permission. On this scheme the ridge height change added no floorspace, so the liability was unaffected.
Records kept for the building control file
Keep the planning amendment record and the building control record in step. They are separate consents and a change can need both, or only one.
The brick substitution needed a planning amendment and nothing from building control. The ridge height change needed a planning amendment and a revised structural submission. The additional rooflight needed neither in planning terms beyond the amendment, but did need a check against the fire strategy for the roof.
Hold the following together: the original decision notice, each amendment decision with its drawing list, the discharge of condition approvals, the controlled drawing register, and the correspondence confirming which route each change took. A conversion where an unexpected ground condition forces changes mid-build creates the same paper trail problem, as the walkthrough of a conversion where contamination was found mid-build shows.
What would have happened if the works had gone ahead first
Building the ridge height change before the section 73 was granted would have put the development out of accordance with the approved plans. That is a breach of condition, enforceable by notice, and in the worst case it puts the whole permission in doubt because what has been built is not what was permitted.
Retrospective applications are available and often granted, but they are granted on the authority's terms, at a time of the authority's choosing, with the building already standing. Lenders and purchasers' solicitors read the planning history, and an unresolved discrepancy between the approved drawings and the as-built position is the kind of thing that delays a sale. A similar problem arises where a scheme's commercial basis shifts after permission, as described in the walkthrough of how viability changed the affordable offer on a mixed-use scheme.
Apply first. It is slower by four weeks and costs a great deal less.
If you need the supporting statement for a section 73 or a non material amendment, the full report index shows where it sits alongside the rest of the pack.
This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
What counts as a non material amendment?
There is no statutory definition in section 96A of the Town and Country Planning Act 1990. The authority judges it in context, asking whether the change would have altered the original recommendation, whether a neighbour would have had anything new to say, and whether it conflicts with the description of development or the reason a condition was imposed.
How long does a section 96A application take?
Twenty-eight days is the prescribed period, and no publicity or consultation is required, which is most of the reason it is faster than a section 73 application. The fee is a modest fixed amount, indexed annually, so check the current schedule rather than relying on a figure from a previous project.
Can I appeal if a non material amendment is refused?
No. There is no right of appeal to the Planning Inspectorate against refusal of a section 96A application. The realistic options are to resubmit a narrower amendment, to apply under section 73 instead, or to seek judicial review of the decision. That is a good reason to put borderline changes into a section 73 from the outset.
Does a section 73 permission repeat the original conditions?
A section 73 permission is a new permission with its own complete condition schedule and its own time limit for implementation. Read the schedule against the original rather than assuming the conditions are identical, because wording is sometimes updated and already discharged conditions are often restated.
What happens if the works are built before the amendment is granted?
The development is then out of accordance with the approved plans, which is a breach of condition enforceable by notice, and in the worst case casts doubt on whether the permission has been implemented at all. A retrospective application may well succeed, but on the authority's terms and timetable, with the building already standing.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.