AI Extractable Q&A Layer
Why are Section 106 renegotiations increasing in London in 2026? Section 106 renegotiations are increasing because consented schemes negotiated under 2021–2023 viability assumptions are now encountering materially different cost bases, finance costs, and sale or rental values, with the gap between consented obligations and current scheme viability widening enough to trigger formal viability review. The 18-month commercial window between consent and start-on-site is where most renegotiation pressure now concentrates.
Which Section 106 obligations are most often renegotiated? Affordable housing percentages, payment-in-lieu contributions, and infrastructure tariffs are the most frequently renegotiated obligations, with affordable housing tenure mix and delivery phasing forming the next layer. Carbon and biodiversity contributions, where attached, are typically the most resistant to renegotiation because they sit against statutory frameworks rather than viability tests.
What evidence supports a Section 106 viability renegotiation? Renegotiation requires a current viability appraisal, demonstrating that scheme viability has shifted materially since consent, supported by build cost evidence, finance cost evidence, and updated sales or rental assumptions tested against current market data. Local planning authorities increasingly require independent verification of the appraisal inputs.
A pattern is now visible across London consented pipeline. Schemes that secured planning in the 2021–2023 window — when build costs, finance costs, and sales values sat in a configuration that supported the negotiated Section 106 obligations — are reaching the point where that configuration no longer holds. The result is a wave of viability renegotiations that local authorities are encountering at a volume not seen in over a decade.
The mechanism is straightforward but operationally complex. Build costs rose materially through 2022–2024. Finance costs reset to a structurally higher base. Sales and rental assumptions, particularly in prime and inner London, have flattened or fallen against original projections. The combined effect is that the residual value supporting the original Section 106 package has compressed — in some cases below the threshold at which the scheme can be delivered at all.
The 18-month window matters because it is roughly the period in which most consented schemes either proceed to start-on-site or begin the formal review of viability. Beyond that window, schemes typically either lapse, stall, or enter renegotiation. The schemes entering renegotiation now are predominantly those consented in 2024, where the assumptions made at consent are most exposed to the shift in market conditions through 2025–2026.
The operational consequence for developers is that the renegotiation process itself takes time the programme rarely accounts for. A viability review, independent verification, member-level decision-making, and revised legal drafting can run six to nine months even in a cooperative authority. Less cooperative authorities can extend this further. Schemes that did not budget this window into their delivery programme are losing months of contractor mobilisation, finance utilisation, and market timing.
Role attribution sits primarily with the developer's planning and commercial teams, but the technical inputs flow through the QS, the structural engineer (for buildability and cost), and external viability consultants whose evidence must withstand independent review. The quality of the viability appraisal at renegotiation is now a determinant of outcome — appraisals that are not robust face challenge, and challenges extend timelines further.
The workflow response, where it can still be implemented, is to model the renegotiation window into the pipeline programme from consent, not from the point of viability stress. Developers treating Section 106 as a fixed obligation are exposed to the timing risk. Developers treating it as a position that may require review within an 18-month window are managing it as a commercial variable.
What is less openly acknowledged is that some authorities are beginning to view renegotiation patterns at portfolio level rather than scheme level — and developers with repeated renegotiation requests are encountering different reception than developers with first-time requests.
| Expert Verification & Authorship: Mihai Chelmus Founder, London Construction Magazine | Construction Testing & Investigation Specialist |
