Permission is not the end of the story
by David Maddox, Founder
Published 14 January 2026
Planning permissions are often treated as fixed moments. A scheme is negotiated, assessed, reported, resolved, signed and issued. The permission becomes the reference point: the approved drawings, the agreed conditions, the Section 106 obligations, the affordable housing schedule, the viability position. In theory, the deal is done. In practice, development rarely behaves so neatly.
Large schemes change. Markets move. Build costs rise. Finance terms harden. Registered provider appetite shifts. Fire safety requirements evolve. Phasing strategies are revisited. Contractors price risk differently. A permission that looked deliverable at committee can, two years later, sit awkwardly between policy ambition and commercial reality.
That is the context for the recent Ministerial letter to the Planning Inspectorate on modifying planning obligations. Its subject is technical: Section 73 applications, Section 106 agreements, viability and the future role of Section 73B. But the wider message is more significant. Government is trying to make the post-permission system more pragmatic without allowing planning obligations, particularly affordable housing, to be casually unpicked.
The letter recognises the pressure facing housebuilding. It refers to the impact of the pandemic, increased construction costs, high interest rates, regulatory changes and wider economic conditions, with particular pressures in London. It also acknowledges the linked problem of reduced demand for Section 106 social and affordable homes, including the growing difficulty of placing agreed affordable units with registered providers.
That acknowledgement matters. For years, the planning system has tended to assume that once affordable housing obligations are secured, delivery will follow. That assumption is now less reliable. On some schemes, the affordable housing obligation remains on paper, but the route to delivering it has become uncertain. The result can be a frozen consent: politically hard to reopen, commercially hard to build, and practically useless as a source of homes.
The Government’s position is therefore deliberately balanced. It accepts that, in specific circumstances, existing planning obligations may need to be modified to improve the viability of housing developments in the near term. It also states that local planning authorities are expected to adopt a pragmatic approach when responding to requests to renegotiate Section 106 obligations. That is the flexible part of the message. The caution comes immediately after it.
The letter is clear that the proper statutory route for modifying or discharging planning obligations is Section 106A of the Town and Country Planning Act 1990. That route is usually effected through a deed of variation. The Government also recognises the practical constraints of that route and is considering whether better mechanisms are needed, but it has not said that Section 73 can become a general shortcut for reopening every part of a planning deal.
For applicants, this is the key point. Section 73 remains a useful tool, but not an all-purpose reset button.
Section 73 allows an applicant to seek a new planning permission without complying with conditions attached to an existing permission. It is routinely used to vary approved plans conditions, adjust phasing, amend technical requirements, update compliance triggers or secure changes that fall within the limits of the original description of development. It is often faster and more proportionate than a full fresh application.
But Section 73 has limits. It cannot be used to change the description of development itself. It is directed at conditions, not the entire permission. Where a Section 73 application is then used as the platform for changing associated Section 106 obligations, the relationship between the proposed condition variation and the obligation change becomes critical.
The Ministerial letter draws that distinction carefully. Attempts to revisit fundamental issues of viability or planning obligations through Section 73 applications should be scrutinised carefully. Applicants should provide robust justification for changes to obligations associated with the original permission, especially where those changes go beyond the specific variation of condition being sought.
That is a sensible warning. A modest amendment to a plans condition should not automatically open the door to a wholesale renegotiation of affordable housing. Equally, where the variation is genuinely linked to delivery, phasing, viability or a material change in scheme economics, there may be a legitimate case for revisiting the obligations.
The practical question is not whether Section 73 can touch a Section 106 agreement. It often can, through a deed of variation or carefully drafted continuation clauses. The real question is whether the proposed change is properly justified and proportionate.
This is where affordable housing becomes the most sensitive issue. The letter expressly addresses Section 73 applications that seek to reduce affordable housing provision based on a new viability assessment. Decision makers are told to have regard to the harm caused by such a reduction and give it appropriate weight in the planning balance, alongside the wider merits of the scheme. That is not a prohibition. It is an instruction to weigh the harm properly.
For developers, that means a revised viability case will need to be more than a spreadsheet showing reduced profit or increased cost. It will need to explain why the original obligation now prevents or materially delays delivery, what has changed since permission was granted, why the proposed reduction is no greater than necessary, and what benefits would be secured by unlocking the scheme. The argument is strongest where the alternative is not a fully policy-compliant scheme, but no scheme at all.
For local planning authorities, the letter supports a more commercially realistic approach, but it does not remove the need for discipline. Authorities will need to test whether the claimed delivery problem is genuine. They will need to consider whether review mechanisms, deferred contributions, tenure changes, grant funding, phasing revisions or registered provider engagement could preserve more affordable housing. A pragmatic approach does not mean accepting the first reduced offer.
The best cases will be evidence-led. They will show a clear change in circumstances, a credible delivery programme, an updated procurement or funding position, and a direct link between the proposed obligation change and the ability to start or continue development. The weakest cases will look opportunistic: a fresh viability appraisal bolted onto an unrelated Section 73 application in the hope of reopening an old bargain.
The letter also sits within a wider reform agenda. Section 73B, introduced by the Levelling-up and Regeneration Act 2023 but not yet in force, is intended to become a new route for varying planning permissions. It is designed to deal with general post-permission changes more pragmatically, including cases where the limitations of Section 73 have caused difficulty. The Government says it will provide guidance on the appropriate use of Section 73B, Section 73 and Section 96A.
That future guidance will be important. At present, the post-permission toolkit is imperfect. Section 96A is too narrow for many real changes. Section 73 is useful but legally constrained. A fresh full application can be disproportionate and risky. Section 73B should, in principle, fill part of that gap by allowing legitimate variations where the resulting scheme is not substantially different from the original permission.
But the Ministerial letter also gives an early warning about the limits of Section 73B. It is expected to become the key mechanism for legitimate variations in response to changing circumstances, but it is not intended to make it easier for developers to reduce planning obligations already entered into, including affordable housing.
That tells us how Government wants the system to evolve. More flexibility on the permission; more caution on the obligations. Easier adaptation of schemes where circumstances change; not an open invitation to dilute the public benefits that justified the original consent.
For practitioners, the drafting implications are immediate. Section 106 agreements need to deal clearly with future amendments. Well-drafted agreements should include provisions confirming how obligations apply to permissions varied under Section 73, and, in due course, how they interact with Section 73B permissions. Poor drafting creates uncertainty, delay and unnecessary legal work. Worse, it can leave parties arguing over whether obligations bind the varied permission at all.
Applicants should also think carefully before choosing the route. A non-material amendment may be sufficient for minor drawing or wording changes. A Section 73 application may be appropriate where the change is properly condition-led and sits within the existing description. A Section 106A application or deed of variation may be required where the real issue is the obligation itself. Once Section 73B is commenced, it may become the better route for wider but not substantially different amendments.
The commercial lesson is straightforward: post-permission strategy now matters almost as much as application strategy. It is no longer enough to secure a permission and assume it can be tidied up later. Conditions, obligations, triggers, review mechanisms and amendment clauses need to be drafted with delivery in mind. That includes anticipating future phasing changes, funding requirements, affordable housing procurement, infrastructure timing and market movement.
The Ministerial letter is not a dramatic policy reset. It is more useful than that. It is a signal to decision makers that delivery problems are real, that obligations may sometimes need to move, and that authorities should respond pragmatically. But it is also a warning to applicants that viability cannot be reopened lightly and that affordable housing reductions will carry planning harm.
The planning system is being asked to do something difficult: preserve the integrity of negotiated public benefits while accepting that rigid obligations can sometimes stop development altogether. That balance will not be struck by slogans about flexibility or certainty. It will be struck case by case, through evidence, drafting and judgement.
Permission, in other words, is no longer the end of the story. For many schemes, it is the beginning of a second planning exercise: keeping the consent alive, coherent and capable of being built.