Key Takeaways: Planning for Strategic Urban Extensions Roundtable

In July, we brought together leading voices in planning, design and infrastructure to discuss the complex landscape surrounding strategic urban extensions.

With contributions from planning director, Megan Wilson, urban design associate director, David Kemp and partner at i-Transport, Greg Jones, the roundtable highlighted a pressing need for greater certainty, clarity and collaboration in the planning and delivery of large-scale developments.

Uncertainty undermining the planning system

The roundtable painted a challenging picture of today’s planning climate. While the system aspires to be plan-led, in practice it remains unpredictable, with local plans often collapsing late in the process, leaving developers without a framework.

There is also a shift towards “planning by appeal” as developers look to secure permissions amid rising risk and reduced confidence in local plan-led delivery. Furthermore, developers are under pressure to make applications appeal-proof, navigating around shifting policies and strained local authority resources.

A lack of central government understanding around costs, risks and delivery timelines is compounding the problem. Local authorities, meanwhile, are struggling with underfunding, inconsistent resources and resistance to change from communities.

Designing places that work – vision vs context

The evolving design approaches behind strategic urban extensions was highlighted, including two dominant philosophies that are shaping masterplanning.

Firstly, contextual design, which evolves organically from the site’s existing landscape and infrastructure. Secondary, visionary design, which starts with a bold future vision and works backwards to build a roadmap.

The political vale of design quality has fluctuated over the years. A renewed emphasis with the implementation of design codes appears to be waning.

However, the politics of design continue to influence outcomes. While national design codes and frameworks have been introduced, local delivery remains patchy and unclear with questions about who owns and will enforce the district-wide codes.

The strongest design codes are simple, principle-led and landowner-driven; focused on ‘must-haves’ rather than aspirational ‘nice-to-haves’; and most effective when they reflect realistic implementation goals, not just compliance.

Transport and infrastructure – a burden on the private sector

The infrastructure challenge was addressed, particularly around sustainable transport. In the absence of a strong national transport strategy, developers are increasingly responsible for enabling sustainable travel, often without adequate support or incentives.

There is also an ongoing disconnect between national ambitions and local delivery mechanisms, making innovation risky and expensive, and many schemes still default to car-centric layouts, with on-plot parking dominating designs.

Yet, there is opportunity. Good strategic transport modelling can enable phased delivery, better long-term planning and reduced risk.

Furthermore, developers that proactively engage with transport authorities can unlock early wins and avoid delays.

And finally, emphasising walkability, cycling and transit from the outset – not as an afterthought – creates more resilient, future-ready communities.

Strategic barriers and market realities

While sustainable infrastructure is more viable in high-value markets, such as the south east, weaker returns in lower-value regions make innovative solutions harder to deliver.

This deepens regional inequalities and entrenches conventional car-based planning in areas least able to absorb infrastructure costs.

Viability remains a critical issue. With infrastructure costs averaging nearly £950,000 per acre in the south, funding shortages are widespread. The planning process, once navigated, often leads straight into cost-driven compromises on quality and ambition.

A more deliverable future

The roundtable concluded by saying that certainty is key – for communities, developers and local authorities alike.

Delivering strategic urban extensions at scale requires more robust, consistent local plans; genuine collaboration between public and private sectors; design and infrastructure strategies that are both aspirational and implementable; and joined-up policy framework that enables long-term thinking and supports innovation without pushing all the risk onto developers.

As the political and planning landscape evolves, delivering sustainable, liveable and viable urban extensions will depend on getting these fundamentals right.