Making the original section 106 bind a section 73 permission

A permission granted under section 73 of the Town and Country Planning Act 1990 is a new permission, not an amendment to the old one. So the question of whether the section 73 and existing section 106 agreement fit together comes down to drafting: if the agreement defines the development or the permission by reference to the original consent only, the obligations may not bite on the new permission at all. The High Court made that point plainly in Norfolk Homes Ltd v North Norfolk District Council in 2020, and it has changed how these deeds are written.

The practical consequence is uncomfortable. A developer can implement a section 73 permission and find the affordable housing obligation unenforceable, or find that it is enforceable and they have accidentally triggered two sets of contributions.

Why this catches people out

Section 73 is used constantly for minor changes: a revised house type, a different materials schedule, a longer implementation period, a varied phasing condition. It feels administrative. The legal effect is not administrative at all, because the grant creates a fresh permission sitting alongside the original one, with its own conditions and its own commencement position.

Planning obligations under section 106 are different again. They are covenants that run with the land and bind successors in title, registered as a local land charge. They are not conditions on a permission, so they do not travel with a permission automatically. Whether they apply to a later permission is a matter of construction of the deed.

Most agreements written before around 2015 define "the Development" or "the Planning Permission" tightly, by application number and date. Many written since then use wider language intended to catch section 73 permissions. Read the actual deed. Do not assume the drafting is modern.

The original permission remains extant

This is the part that creates the trap. Granting a section 73 permission does not extinguish the original. Both subsist, and the developer chooses which to implement.

That choice has consequences:

• If the original permission has been implemented and the section 73 permission is then also partly implemented, the question of which permission the works were carried out under can become difficult, particularly where the two differ in phasing.
• If the obligation is tied to the original permission and the developer implements only the section 73 permission, the obligation may never be triggered, which sounds like good news and usually is not, because the council will have spotted it and will refuse to issue the section 73 consent until a supplemental deed is completed.
• If the obligation is drafted to catch any permission for development on the land, implementing the section 73 permission can trigger the same contribution twice unless the deed accounts for it.

Councils now routinely treat completion of a supplemental deed as a condition precedent to issuing the section 73 decision. That is sensible practice, and it means the deed is on the critical path of what looked like a two-month application.

Whether the obligation bites on the new permission

Work through the deed in this order.

1. Find the definition of the Permission or the Planning Permission. Note whether it refers to a specific application reference, or to that permission "and any permission granted under section 73 in respect of it".
2. Find the definition of the Development. Some agreements define it by reference to the approved drawings, which a section 73 permission will have changed.
3. Check the trigger events. Contributions are usually tied to commencement of development, implementation, or occupation of a stated number of units, each defined within the deed.
4. Check whether the obligations are expressed to bind the land generally or only on implementation of the defined permission.
5. Check the reciprocal covenants. Where the council covenants to apply a contribution to a stated purpose, that covenant also needs to survive.

Where the definitions are tight to the original consent, you need a supplemental deed. Where they are wide, you need to check the arithmetic rather than the principle, because a deed that catches every permission can produce double counting.

Supplemental deeds and how they are drafted

A supplemental deed under section 106 is a straightforward document that does a small number of things precisely. It recites the original agreement and the original permission, defines the new section 73 permission, and then either extends the existing obligations to the new permission or restates them as varied.

The drafting points that matter:

• Make clear that obligations already performed are not performed again, and credit sums already paid.
• Deal expressly with which permission may be implemented, and whether implementation of one releases the other.
• Carry across any review mechanism with its original trigger dates, or reset them deliberately. The way those mechanisms are structured is set out in affordable housing review mechanisms in section 106.
• Bring in every party with an interest in the land, including mortgagees, or the deed will not bind the title.
• Check whether the original agreement contains a prohibition on implementing any other permission for the site, which some do.

Where the variation changes the scheme enough to alter the obligations themselves, this is no longer a supplemental deed exercise. A reduced unit count or a changed mix can justify revisiting the affordable housing position, which brings the Viability Assessment and the Affordable Housing Statement back into play, and a council will expect evidence rather than assertion.

Note that section 106A allows an agreement to be modified or discharged by agreement at any time, and unilaterally after five years, which is a separate route from the supplemental deed and occasionally the better one. The position where an obligation has outlived its purpose is covered in discharging a section 106 obligation that no longer serves.

Risk of implementing the wrong permission

Before anyone starts on site, write down which permission is being implemented and why. Then check that the pre-commencement conditions of that permission have been discharged, because the two permissions will have different condition numbers and the discharge applications are usually made against only one of them.

A common and avoidable failure is discharging conditions against the original permission, then building out the section 73 scheme. The works are then unauthorised in respect of conditions that were never discharged on the operative permission, which is an enforcement exposure and a problem on sale.

Record the decision in a short implementation note held with the title file. It takes an hour and it answers the question a purchaser's solicitor will ask three years later.

Land registry and the charges register

A section 106 agreement is registrable as a local land charge, and the supplemental deed should be registered in the same way. On registered land, check whether the original agreement was also noted on the charges register at the Land Registry, and make sure the supplemental deed follows the same route.

Buyers and funders rely on those entries. A supplemental deed that exists but was never registered creates exactly the kind of discrepancy that stalls a sale, and it costs almost nothing to get right at completion.

A checklist before implementation

Read the deed's definitions of the permission and the development. Establish whether a supplemental deed was completed and registered. Confirm which permission is being implemented. Confirm the pre-commencement conditions on that permission have been discharged. Confirm which contributions have been paid and against which trigger. Confirm the review mechanism dates. Then start.

One honest uncertainty: the Levelling-up and Regeneration Act 2023 inserted a new route for amending permissions, and its commencement and interaction with existing obligations should be verified against the current government position rather than assumed, as at the date you are reading this.

For the wider picture on whether obligations follow a varied permission, see do section 106 obligations carry over to a section 73 permission. To draft the supporting statements around a section 73 application, see PlanScope pricing.

This is general guidance, not legal advice; take advice from a planning solicitor on the construction of any particular agreement 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.