Grey belt is unlocking new housing – but what else is needed to make sites viable?
There’s a lot to unpack when it comes to the government’s fledgling grey belt land categorisation.
It has undeniably helped unlock approvals for new homes, while also exposing, and in some areas deepening, key challenges around viability.
It’s a complex and evolving picture, but one that also presents new and exciting opportunities for developers.
That was one of the main takeaways from The Grey Belt Debate panel session at the National Planning Conference 2025, chaired by TerraQuest’s Daniel Williams, with expert insight from Rebecca Phillips (Planning Inspectorate), Megan Wilson (Planning Director, Marrons), Annette Roberts (South Staffordshire Council), and Mark Skilbeck (Taylor Wimpey).
Read on for some key insights from the panel – with key advice on how to make the new land categorisation work for you.
Whilst grey belt looks here to stay, developers need more clarity
Rebecca explained that the National Planning Policy Framework changes introduced in December last year mark a significant shift - moving from a discretionary to a mandatory requirement for local authorities to review green belt boundaries where housing needs cannot be met elsewhere.
She underlined that this is part of a new “sequential” approach, requiring councils to consider brownfield first, then grey belt, then green belt if necessary. While this represents a major policy change, she said the landscape remains “formative”, with more guidance expected as case law develops.
She also highlighted a recent High Court judgment confirming that the NPPF’s aim of preserving the openness of the green belt still applies – which should provide confidence and certainty, and noted that we’re seeing a sequence of early appeals helping to clarify the government’s intentions.
The viability question
A clear theme throughout was viability. All panellists agreed that even with new land designation, the economics of delivery remain difficult – particularly when striving to meet golden rules.
Mark Skilbeck of Taylor Wimpey confirmed that developers are reluctant to promote schemes they can’t viably deliver:
“We want to spend the money, time and effort on schemes we can actually deliver.”
He warned that current viability guidance is “undermining the policy objective of getting things delivered” and called for a review to ensure grey belt ambitions translate into actual homes on the ground.
Helpfully, Skilbeck outlined different options for promoting grey belt schemes, particularly where the golden rules make viability tight.
Developers, he said, can:
- Wait to promote schemes through local plan updates, especially where authorities acknowledge 50% affordable housing may not be viable.
- Push forward under existing development plan routes, where material benefits such as new housing, jobs, and community infrastructure demonstrate very special circumstances.
- Rely on previously developed land policies, which allow progress outside of the golden rules, where brownfield credentials strengthen the case.
Mark emphasised that, the best option would be for government revise its viability framework to allow for site-specific assessment – something he hopes to see happen in the future.
The panel agreed that while the policy seeks to unlock housing land, grey belt doesn’t automatically make development cheaper.
Mark added that infrastructure, schools, hospitals, and other essentials “haven’t got any cheaper - they’ve gone the other way.”
Early signs from appeals and applications
Megan Wilson offered a brilliant perspective on legally supporting grey belt/green belt schemes, with special emphasis on how they really valued working with a council like South Staffordshire that were open to reviewing their greenbelt designations.
She highlighted findings from recent research by Marrons looking at the first months of grey belt decisions. It found that:
- 57% of appeals related to grey belt land were allowed during it’s first year, making the % of allowed appeals higher than those dismissed
- Around 1,600 dwellings have been permitted that likely wouldn’t have been before grey belt categorisation.
- However, regional disparities on greybelt are significant, with over half of decisions in the South East and just 1% in the North.
Wilson said these finding paint a “a broadly positive picture” - particularly at appeal - though local authorities are still adapting to the new approach. She also emphasised that the regional disparity – with grey belt not performing as strongly in the north – highlights there needs to be an urgent regionally-focused look at viability challenges.
You can read the full Marrons and LPDF research report, Grey Belt: A Game Changer for Planning and Housing, here.
Local authority perspective
Annette Roberts, from South Staffordshire Council - a district that is around 85% green belt - said their council initially anticipated a rush of grey belt applications, but that hadn’t materialised.
“We thought we might need a better letterbox to receive all the applications – even though they mostly come digitally” she joked, “but that hasn’t happened.”
She suggested this was again probably largely down to viability and uncertainty, suggesting both of these need to be looked at urgently.
“In some ways what government gave with one hand, it took away with the other.”
Roberts said greater clarity on viability and the ‘golden rules’ would help both planners and communities feel more confident about what development on grey belt means for them.
Avoiding ‘planning by appeal’
Both Wilson and Skilbeck warned that too much early grey belt progress is being driven through the appeals system rather than local plans.
Mark Skilbeck said: “As an industry, we need the comfort and confidence of sustainably planned schemes through the development plan.”
Megan Wilson agreed, stressing the need for training and outreach, to help members and residents understand what grey belt is, and isn’t.
“Local residents at appeal hearings often misunderstand it as green belt,” she said. “We need to take the politics out of grey belt and focus on education and viability.”
Post permission barriers: ecology, surveys and infrastructure
Megan Wilson also pointed out that gaining planning permission is “just the first hurdle”.
Ecological surveys, infrastructure agreements and licensing can all add long delays before construction can begin.
Mark Skilbel echoed these sentiments:
“There are sites with planning permission that we can’t build due to changing circumstances post-outline,” citing issues like nutrient neutrality and infrastructure capacity. “That needs to be addressed urgently.”
Unlocking delivery post permission is undoubtedly a huge sticking point for the success of grey belt. Whilst ultimately a tweak to planning policy – approvals are only as meaningful as the new sites – and homes – they can eventually lead to.
Looking ahead
So where does grey belt go next? As outlined by Rebecca from PINS, there will undoubtedly be more guidance to come – and ongoing appeal decisions and court rulings are already helping the sector have a clearer image of the new categorisation.
Viability remains the sticking point – but panellists put forward their hopes and ambitions, both for more realistic measures on viability and for more collaboration across districts and councils nationally.
Towards the end of the session, Annette Roberts poignantly underlined that more clarity and community conversation will be essential in helping the policy to be well-received long term:
“There’s a significant amount of uncertainty and concern in communities. The sooner we can clarify that and start to talk about development in a positive way, the better chance we have of delivering sustainable growth.”
Short on time? Here are the key takeaways
- The grey belt policy represents a major structural shift in land release priorities.
- Viability remains the critical barrier to delivery, but developers still have multiple routes to promote grey belt schemes.
- It’s essential we address sustainability and infrastructure challenges to ensure delivery.
- Early results from appeals show promise, but also strong regional disparities.
- Local plan confidence, not appeals, should be driving grey belt delivery.
- Clearer guidance and communication with communities will be vital for long-term success.
