Why are approved housing developments in London not starting construction in 2026? In London, thousands of residential units with full planning consent are not progressing to construction. Across the capital, approved schemes remain stalled for extended periods before works begin, highlighting a widening gap between consent and delivery. The housing challenge is no longer defined by how quickly permission is granted, but by whether projects can move from approval to site under increasing financial, regulatory and logistical pressure.
This shift reflects a structural change in London development. While planning approvals continue, delivery is increasingly constrained by viability, infrastructure capacity and regulatory requirements under the Building Safety Act. The critical risk point now sits between planning approval and mobilisation, where funding, compliance and pre-construction complexity determine whether schemes proceed or remain stalled.
In this environment, planning consent no longer guarantees construction. Housing delivery in London has become a multi-stage constraint system, where each stage introduces its own risk to programme. Understanding the gap between consent and construction is now essential to understanding why schemes are not progressing despite having permission.
Housing delivery in London can no longer be assessed by planning approvals alone. The transition from consent to construction is governed by a combination of financial viability, regulatory compliance, infrastructure capacity and procurement readiness. In this environment, planning permission represents only the first stage of delivery, and projects must pass through multiple additional constraints before construction can begin.
Sadiq Khan, Mayor of London, stated in February 2026 that speeding up delivery is critical to supplying the homes Londoners need and confirmed that City Hall is working with government, Homes England and local authorities to unblock the barriers to thousands of new homes. This statement reflects a shift in focus from planning policy to delivery intervention, recognising that a significant proportion of schemes are not progressing to construction despite having consent.
Planning Capacity Remains a Constraint, Not a Solution
Planning is still a critical stage in housing delivery, but the challenge in 2026 is increasingly related to capacity rather than policy. ATLAS LDN is targeted at local planning authorities to support applications, masterplans and pre-application processes, highlighting the resource constraints within borough planning teams.
In practice, delays are often driven by:
While planning reforms aim to increase supply, the operational reality is that many boroughs lack the resources to process applications at the speed required for large-scale delivery.
The result is that even before construction begins, projects can experience extended timelines during the planning and pre-construction phase.
The Emergence of the Post-Planning Delivery Gap
A key shift in London’s development environment is the growing importance of what happens after planning consent is granted. NHA LDN specifically targets non-planning and post-planning barriers, indicating that a significant proportion of delays now occur after approval.
This delivery gap typically includes:
Historically, planning approval was a key milestone that triggered construction. In 2026, approval increasingly represents only the start of a complex pre-construction phase that can extend for months or years.
This shift fundamentally changes how housing delivery should be assessed, moving focus from approvals to actual starts on site.
Viability Pressure Is Limiting Project Starts
One of the primary drivers of stalled schemes is financial viability. London’s construction market continues to operate under cost pressure, with inflation in labour, materials and logistics impacting project economics.
At the same time, developments are subject to:
For many schemes, particularly residential developments, the combination of rising costs and fixed or constrained sales values means that projects are no longer viable under their original appraisals.
This leads to:
The presence of support programmes aimed at unlocking sites suggests that viability is now a central barrier to delivery, not a secondary consideration.
Infrastructure and Logistics Constraints Affect Delivery
In dense urban areas such as London, infrastructure capacity plays a significant role in determining whether a site can progress.
Constraints typically include:
These factors can delay mobilisation, restrict construction methodologies, and increase costs.
Even where planning permission is in place, a lack of infrastructure readiness or logistical feasibility can prevent projects from starting on programme.
This is particularly relevant in regeneration areas and high-density zones, where multiple projects compete for the same constrained infrastructure.
Regulatory Requirements Are Extending Pre-Construction Phases
The regulatory environment in London has become more complex, particularly for higher-risk residential buildings. Under the Building Safety Act framework, developers must demonstrate compliance before construction progresses, including:
Planning is still a critical stage in housing delivery, but the challenge in 2026 is increasingly related to capacity rather than policy. ATLAS LDN is targeted at local planning authorities to support applications, masterplans and pre-application processes, highlighting the resource constraints within borough planning teams.
In practice, delays are often driven by:
- Limited officer capacity to process complex applications
- Extended validation periods and requests for additional information
- Slow discharge of planning conditions
- Increased scrutiny on design, sustainability and fire safety
While planning reforms aim to increase supply, the operational reality is that many boroughs lack the resources to process applications at the speed required for large-scale delivery.
The result is that even before construction begins, projects can experience extended timelines during the planning and pre-construction phase.
The Emergence of the Post-Planning Delivery Gap
A key shift in London’s development environment is the growing importance of what happens after planning consent is granted. NHA LDN specifically targets non-planning and post-planning barriers, indicating that a significant proportion of delays now occur after approval.
This delivery gap typically includes:
- Delays in securing funding or refinancing schemes
- Challenges in discharging planning conditions
- Design changes required to meet updated regulations
- Procurement delays for contractors and specialist packages
Historically, planning approval was a key milestone that triggered construction. In 2026, approval increasingly represents only the start of a complex pre-construction phase that can extend for months or years.
This shift fundamentally changes how housing delivery should be assessed, moving focus from approvals to actual starts on site.
Viability Pressure Is Limiting Project Starts
One of the primary drivers of stalled schemes is financial viability. London’s construction market continues to operate under cost pressure, with inflation in labour, materials and logistics impacting project economics.
At the same time, developments are subject to:
- Section 106 obligations, including affordable housing requirements
- Increased sustainability and performance standards
- Higher financing costs due to interest rate conditions
For many schemes, particularly residential developments, the combination of rising costs and fixed or constrained sales values means that projects are no longer viable under their original appraisals.
This leads to:
- Delayed starts while developers reassess viability
- Phased delivery strategies to manage risk
- In some cases, sites remaining undeveloped despite having planning permission
The presence of support programmes aimed at unlocking sites suggests that viability is now a central barrier to delivery, not a secondary consideration.
Infrastructure and Logistics Constraints Affect Delivery
In dense urban areas such as London, infrastructure capacity plays a significant role in determining whether a site can progress.
Constraints typically include:
- Limited access for construction logistics and HGV movements
- Utility capacity, including power, water and drainage connections
- Coordination with existing transport infrastructure, including rail and road networks
- Restrictions related to working hours, noise and environmental controls
These factors can delay mobilisation, restrict construction methodologies, and increase costs.
Even where planning permission is in place, a lack of infrastructure readiness or logistical feasibility can prevent projects from starting on programme.
This is particularly relevant in regeneration areas and high-density zones, where multiple projects compete for the same constrained infrastructure.
Regulatory Requirements Are Extending Pre-Construction Phases
The regulatory environment in London has become more complex, particularly for higher-risk residential buildings. Under the Building Safety Act framework, developers must demonstrate compliance before construction progresses, including:
- Detailed design development prior to approval
- Clear documentation of structural and fire safety strategies
- Evidence to support regulatory submissions
This shifts risk into the pre-construction phase, requiring more time for design coordination, review and approval.
The effect is a longer period between planning consent and site mobilisation, particularly for larger or more complex residential schemes. In this context, regulatory compliance is not simply a legal requirement but a programme driver, influencing when and how projects can proceed.
Housing Delivery Is Now a Multi-Stage Constraint Problem
The introduction of programmes such as NHA LDN and ATLAS LDN reflects an acknowledgment that housing delivery is constrained across multiple stages, not just planning.
The key barriers in 2026 can be summarised as:
- Planning capacity limitations within boroughs
- Post-planning delays in funding, design and procurement
- Viability challenges driven by cost and market conditions
- Infrastructure and logistics constraints in dense urban areas
- Increasing regulatory requirements affecting pre-construction
Each of these factors can independently delay a project. Combined, they create a cumulative effect that slows overall delivery across London.
What This Means for Construction Delivery in London
For contractors, consultants and developers, the current environment requires a shift in how projects are planned and assessed.
Key implications include:
- Longer pre-construction periods should be assumed as standard
- Early engagement with planning authorities and regulators is essential
- Viability assessments must be regularly updated to reflect market conditions
- Logistics and infrastructure constraints need to be addressed early in programme development
- Greater emphasis on design certainty before construction begins
The concept of shovel-ready sites is increasingly difficult to achieve in London, as multiple layers of approval and coordination are required before works can commence.
Evidence-Based Summary
London’s housing delivery slowdown in 2026 is not driven by a single constraint but by a combination of planning capacity, post-planning delays, viability pressure, infrastructure limitations and regulatory requirements. While policy initiatives aim to accelerate delivery, the need for programmes specifically targeting stalled or slow-moving sites indicates that the challenge lies in the transition from consent to construction.
In practical terms, planning approval no longer guarantees delivery. The critical phase for London housing is now the period between permission and mobilisation, where financial, technical and regulatory factors determine whether a scheme progresses or remains stalled.
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Expert Verification & Authorship: Mihai Chelmus
Founder, London Construction Magazine | Construction Testing & Investigation Specialist |
