Podcast Episode #16: Material Matters, Cut and Fill
May 5, 2026
Explore how early cut and fill strategy, sequencing and on‑site material management shape cost, programme and environmental outcomes on development projects.
Two years after the Home Builders Federation (HBF) first highlighted the scale of unspent developer contributions, more than £8 billion in S106 and CIL remains unused across England and Wales, with a significant portion dormant for over five years. For developers, it raises a critical question: if infrastructure isn’t being delivered, are these obligations still proportionate or commercially justified? This article explores why the issue persists and how reviewing triggers, outdated requirements and opportunities for modification or claw-back can turn S106 from a fixed liability into an actively managed commercial tool that protects viability and unlocks value.
Two years after the Home Builders Federation (HBF) first highlighted the scale of unspent developer contributions, the picture has not materially changed. In its refreshed analysis looking at the position in 2025, the data still points to a significant backlog of funds sitting with local authorities rather than being deployed into infrastructure.
Latest figures indicate that more than £8 billion of developer contributions remain unspent across England and Wales. This includes over £6 billion secured through Section 106 agreements and close to £2 billion collected through the Community Infrastructure Levy.
A sizeable proportion of this money has now been sitting unspent for more than five years. While these funds are often technically allocated to projects, the reality is that delivery delays, changing priorities and programme slippage mean large sums remain dormant.
For developers, this raises an important strategic question. If infrastructure is not being delivered in line with original assumptions, are the obligations themselves still appropriate, proportionate and commercially justified?
Many live S106 agreements were negotiated under very different market conditions. Since then, the sector has seen major shifts in build cost, funding cost, sales rates and policy direction. Yet agreements are often still treated as fixed cost commitments rather than commercial positions that can be actively managed.
In practice, we regularly see:
Across multi site portfolios, these inefficiencies can translate into millions of pounds of avoidable cost.
The fact that the HBF has revisited this issue two years on is significant. It reinforces that this is not a short term reporting anomaly. It is a structural issue within the system.
If billions of pounds are still sitting unspent years after collection, it strengthens the case for developers to revisit existing obligations and test whether they still meet the legal tests of necessity, proportionality and direct relationship to development.
It also strengthens the commercial argument in negotiations with authorities who are under increasing pressure to demonstrate delivery.
One of the most underused areas of S106 value recovery is claw-back.
Many agreements contain mechanisms that allow funds to be returned if they are not spent within defined timeframes or if specified infrastructure is not delivered. However, these clauses are often poorly understood, inconsistently monitored or simply not activated.
This is a core area we specialise in.
Our work includes:
For clients, this can unlock immediate capital recovery alongside longer term obligation optimisation.
With policy shifting, authorities under pressure to deliver and evidence now showing long term under deployment of contributions, there is a clear window for proactive review.
Developers who audit and challenge legacy obligations now are typically achieving:
The key point is simple. S106 should not be treated as static. It is a live commercial instrument that, when properly reviewed, can unlock real value.
Get in touch with Tori Hall our Development Management Group Director or Ben Wakeling our Head of Cost & Commercial, if you’d like to talk through any of your projects and how we can assist with gaining claw-back.
We’re always happy to share further insight and lessons learned across a wide range of project types. For more specific information on S106 Agreements have a look back on our webinar.
Explore how early cut and fill strategy, sequencing and on‑site material management shape cost, programme and environmental outcomes on development projects.
Rising geopolitical tension does not affect development viability in isolation, but through increasing pressure on energy prices, supply chains and the cost of energy‑intensive materials. Where schemes are progressed on assumptions made under more stable conditions, these pressures can quickly challenge margins, appraisals and deliverability, particularly in a flat housing market. Our article looks at how developers can respond to build cost volatility in a more informed and proportionate way. Drawing on our specialists' experience, it explores how early coordination, design‑led value engineering and integrated decision‑making can help manage cost risk, protect scheme viability and avoid short‑term measures that compromise long‑term quality and value.
Welcome to our April 2026 newsletter. In this month's Brookbanks newsletter, learn more about how high-rise developments can be made more deliverable, with guidance on how you can reduce risk and protect viability. We're also looking back on our April webinar, where Annabel Le Lohe and Katherine Peers gave a rundown of Environmental Impact Assessments and how coordination can make a real impact on project delivery. Plus, there's a recap of this month's podcasts featuring two special guests. Paul Smith, Managing Director at The Strategic Land Group, and Tom Park, Associate Development Director at Caddick Developments. Also, find out which members of our team will be at UKREiiF as well as more about the CPD event we're co-hosting with the LPDF in May.