Section 73 vs Section 96A: Changing Approved Planning Maps and Plans

Few building projects progress from architectural drawings to completed construction without modifications. On site, unexpected ground conditions, structural beam constraints, client design preferences, or budget revisions frequently require changes to building footprints, window positions, rooflines, or boundary fences.

However, once a local planning authority issues a formal Decision Notice, the approved drawings cease to be flexible concepts—they become legally binding statutory instruments. Building something that deviates from those approved drawings without council consent constitutes a breach of planning control under Section 171A of the Town and Country Planning Act 1990.

To regularise changes lawfully, developers and homeowners have two statutory mechanisms under English planning law:

1. Section 96A: Non-Material Amendments (NMAs)
2. Section 73: Minor Material Amendments (Varying Planning Conditions)

This comprehensive guide explains how each procedure works, the statutory tests governing their use, the legal limitations on red-line boundaries, and how to prepare compliant drawing packages and mapping schedules.

Architects and planning consultants coordinate drawing revisions to ensure Section 73 and 96A amendments comply with approved plans.

The Approved Plans Condition: Why Drawings Are Legally Binding

When a local planning authority grants planning permission, the Decision Notice invariably attaches a standard condition (almost always Condition 2 or Condition 3):

"The development hereby permitted shall be carried out in strict accordance with the following approved plans and drawings: Drawing No. PL-01 Rev B (Site Location Plan), PL-02 Rev C (Proposed Block Plan), PL-03 Rev A (Proposed Elevations)..."

If your contractor moves an extension 300 millimetres closer to a neighbouring boundary, widens a garage door, or raises a ridge line by two brick courses without formal planning amendment:

• The development is unauthorised.
• The council can issue a Planning Contravention Notice (PCN) or a formal Enforcement Notice demanding immediate cessation of works or partial demolition.
• Conveyancing solicitors will flag the discrepancy during property sales, potentially stalling or collapsing mortgage financing.

Section 96A: Non-Material Amendments (NMAs)

Introduced by the Planning Act 2008, Section 96A of the Town and Country Planning Act 1990 gives local planning authorities the statutory power to approve non-material changes to an existing planning permission.

+-------------------------------------------------------------------------+
|                  THE SECTION 96A AMENDMENT ROUTE                        |
+-------------------------------------------------------------------------+
|  Scope:        Very small, insignificant changes                        |
|  Statutory:    Section 96A Town & Country Planning Act 1990              |
|  Timescale:    28-day determination window                              |
|  Consultation: No statutory neighbour notification required             |
|  Result:       Amends original permission (does NOT issue new consent)  |
|  Fee:          Lower statutory application fee                          |
+-------------------------------------------------------------------------+

What Qualifies as a "Non-Material" Amendment?

The legislation does not contain a rigid statutory definition of "non-material" because materiality is always a matter of fact and degree assessed by the case officer. However, National Planning Practice Guidance (PPG) and council validation lists generally consider the following to be non-material:

• Moving an external window or door by a minor distance where it does not cause overlooking.
• Omitting a non-structural decorative chimney or parapet wall.
• Substituting approved external brickwork or roof tiles with an identical or superior material of comparable hue and texture.
• Reducing the footprint, depth, or height of an extension (provided the reduction does not alter the architectural balance or breach amenity policies).
• Internal floor plan reorganisations that have no external manifestation.

What Section 96A CANNOT Do: The Red-Line Boundary Rule

There is one absolute statutory restriction: a Section 96A application can never alter, move, or expand the red-line application site boundary.

Under English planning law, the red-line boundary defines the jurisdictional territorial extent of the grant. Changing the boundary alters the legal planning unit and affects third-party land interests. If your revised layout steps outside the red line originally approved, Section 96A is legally unavailable.

The Section 96A Procedure:

• Determination Period: The local authority has a strict 28-day statutory deadline to determine the application (which can be extended by mutual written agreement).
• No Statutory Consultation: The council is not legally required to notify adjoining neighbours, publish site notices, or consult statutory bodies, because the change is deemed non-material.
• Decision Outcome: If approved, the council issues an official Section 96A Decision Letter that attaches to the original planning permission. It does not issue a new planning consent.

Section 73: Minor Material Amendments (Varying Conditions)

Where proposed modifications exceed the threshold of "non-material" but remain within the overall scope of the approved scheme, applicants rely on Section 73 of the Town and Country Planning Act 1990.

Section 73 allows an applicant to apply for planning permission for development without complying with conditions subject to which a previous planning permission was granted. In practice, it is the primary legal mechanism used to vary the "Approved Plans Condition" to substitute a revised drawing set.

+-------------------------------------------------------------------------+
|                    THE SECTION 73 VARIATION ROUTE                       |
+-------------------------------------------------------------------------+
|  Scope:        Noticeable alterations that do not fundamentally change  |
|                the character of the approved development                |
|  Statutory:    Section 73 Town & Country Planning Act 1990              |
|  Timescale:    8-week standard determination window                     |
|  Consultation: Full statutory neighbour and consultee notification     |
|  Result:       Creates a BRAND-NEW standalone planning permission       |
|  Fee:          Standard variation fee (less than full new application)  |
+-------------------------------------------------------------------------+

What Qualifies as a "Minor Material" Amendment?

A Section 73 application is appropriate when:

• Enlarging an extension footprint or repositioning a building on the plot within reasonable tolerances.
• Raising a roof pitch or inserting dormer windows that require daylight/overlooking re-evaluation.
• Re-engineering vehicular access, driveway alignments, or parking bay layouts on the site plan.
• Altering external fenestration extensively (e.g. replacing solid brickwork with large bi-fold glass arrays).
• Modifying phasing conditions or construction management plans.

The Landmark Precedent: Finney v Welsh Ministers 2019

For decades, developers used Section 73 to tweak both conditions and project descriptions. However, in the landmark Court of Appeal ruling Finney v Welsh Ministers 2019 EWCA Civ 1868, the court established a definitive legal boundary:

The Finney Principle: A Section 73 application cannot be used to vary, contradict, or alter the operative description of the development set out in the grant of permission itself.

Practical Example:

• If your original permission was described as "Erection of a single-storey rear extension and detached two-bay garage", you cannot use Section 73 to alter the drawings to build a three-bay garage, because doing so directly contradicts the operative words in the grant.
• If the original description was phrased broadly as "Erection of outbuilding", a variation from two bays to three bays could lawfully be considered under Section 73.

The Wheatcroft Test: Substantially Different Development

Furthermore, Section 73 applications are governed by the established High Court doctrine in Bernard Wheatcroft Ltd v Secretary of State for the Environment 1982:

• An amendment can only be accepted if it does not result in a development that is substantially different in nature or character from that originally approved.
• If the revised drawings alter the whole concept of the development (e.g. converting single-family houses into flats or radically shifting the orientation of a commercial building), the council must reject the Section 73 application and demand a full fresh planning application.

Detailed Comparison: Section 96A vs Section 73

How Section 73 Creates Dual Permissions

One of the most crucial legal characteristics of a Section 73 decision is that it does not erase or replace the original planning permission:

1. Two Parallel Consents: When the local authority approves a Section 73 application, it issues a brand-new Decision Notice. The applicant now holds two valid, independent planning permissions for the same site:
   • Permission A: The original consent subject to original drawings.
   • Permission B: The new Section 73 consent subject to the revised drawings.
2. The Developer's Choice: The developer can lawfully choose whether to build out Scheme A or Scheme B. However, you cannot mix and match parts of both permissions on the same parcel of land without specific legal coordination.
3. Re-imposition of Conditions: When drafting the Section 73 permission, the case officer must re-impose all relevant ongoing conditions from the original permission (such as tree protection, contamination remediation, or highway access works). Any condition omitted from the Section 73 notice ceases to apply to that new permission!

The Drawing Schedule: Presenting Revised Maps to the Council

Whether you are applying under Section 96A or Section 73, validation technicians will reject your submission if you simply upload a loose drawing file without a formal Drawing Comparison Schedule.

To guarantee swift validation, include a structured table in your supporting statement identifying every superseded drawing alongside its replacement:

+-------------------------------------------------------------------------------------------------+
|                                 DRAWING REVISION SCHEDULE                                       |
+------------------------------------+------------------------------------+-----------------------+
| Approved / Superseded Drawing      | Proposed Replacement Drawing       | Summary of Alteration |
+------------------------------------+------------------------------------+-----------------------+
| Drawing No. 2024-04-P01 Rev A      | Drawing No. 2024-04-P01 Rev B      | Site boundary un-     |
| (1:1250 Site Location Plan)        | (1:1250 Site Location Plan)        | changed; north re-set |
|                                    |                                    |                       |
| Drawing No. 2024-04-P02 Rev B      | Drawing No. 2024-04-P02 Rev C      | Rear extension depth  |
| (1:500 Proposed Block Plan)        | (1:500 Proposed Block Plan)        | reduced by 400mm;     |
|                                    |                                    | patio layout shifted  |
|                                    |                                    |                       |
| Drawing No. 2024-04-P03 Rev A      | Drawing No. 2024-04-P03 Rev B      | Bi-fold doors resized |
| (Proposed Ground Floor Plan)       | (Proposed Ground Floor Plan)       | from 3.6m to 3.0m     |
+------------------------------------+------------------------------------+-----------------------+

Essential Mapping Standards for Amendments:

1. Accurate OS MasterMap Base: All replacement block plans and location plans must use licensed, metric-scaled Ordnance Survey MasterMap data. You can generate fresh, compliant 1:500 block plans and 1:1250 site location plans on PlanningMapsUK.
2. Revision Clouding and Deliberate Hatching: Professional architectural technicians use revision clouds (an undulating bubble border) around any modified wall, door, or boundary on the revised drawing, accompanied by a revision triangle (e.g. ▲ Rev C) in the title block. This allows the planning officer to verify the changes in seconds.
3. Metric Dimensions Clearly Annotated: If an extension depth has shifted from 4.0m to 3.6m, annotate the revised distance clearly in metres relative to the untouched boundary line.

When You Must Submit a Full Fresh Application

Neither Section 96A nor Section 73 can be used as a shortcut to bypass proper planning scrutiny. You must withdraw your plans and submit a full fresh planning application under Section 62 if:

• The Red Line Expands: You need to incorporate neighbouring garden land, a private access track, visibility splays, or drainage fields that were outside the original red-line application boundary.
• The Description Contradicts the Scheme: You wish to add new primary elements (such as adding a detached annex or altering a commercial use category) that contradict the operative wording of the original grant (Finney principle).
• The Wheatcroft Threshold Is Exceeded: The scheme introduces substantial changes in scale, design philosophy, height, or amenity impact that would prejudice the rights of neighbouring residents who commented on the original proposal.
• The Original Permission Has Expired: Section 73 cannot be used to resurrect a permission where the statutory commencement period has lapsed without development having been lawfully initiated.

Summary

When altering approved planning drawings, selecting the correct statutory route saves weeks of unnecessary delays and prevents costly enforcement disputes:

• Use Section 96A for minor, unobtrusive adjustments (decided in 28 days without public consultation). The red-line boundary cannot be changed.
• Use Section 73 for noticeable footprint, elevation, or layout amendments that require varying the approved plans condition (takes 8 weeks, involves public consultation, and generates an independent new consent). Remember that Section 73 cannot alter the operative description of the grant.
• Always prepare a structured Drawing Comparison Schedule detailing superseded and replacement drawing references.
• Use licensed, metric-scaled Ordnance Survey vector mapping for all replacement location plans and block plans.

Generate your updated, council-compliant 1:500 block plan or 1:1250 site location plan on PlanningMapsUK today to ensure your planning amendment package passes validation smoothly.