Status	2026 Regulatory Update
Regulator	Building Safety Regulator (BSR)
Applicability	London Higher-Risk Buildings (HRBs) – Completion, Handover & Early Occupation
Compliance Window	Active (Immediate Application)

Introduction

In 2026, phased occupation is one of the most misunderstood areas of the HRB regime. Project teams often assume that partial completion can lead to partial occupation to protect programme and cash flow.

For London HRBs, that assumption can become a hard compliance failure.

Gateway 3 is not a commercial milestone, it is a life-safety approval. If you want partial Gateway 3 approval (phased occupation), you must prove that the occupied area is functionally complete, safely separable and operationally protected from ongoing construction.

This guidance explains what the BSR expects in 2026 and gives a practical checklist for London projects.

1. The BSR’s 2026 Expectation at Gateway 3

At Gateway 3, the BSR does not approve progress. It approves safe occupation.

The regulator expects:

• Operational Life Safety Systems: Commissioned fire alarms, smoke control, emergency lighting, evacuation strategy and access arrangements fully working for the occupied area.
• Confirmed Safety Case Readiness: Clear evidence that safety-critical decisions were implemented, not merely designed.
• Golden Thread Live: Accurate, accessible and owned information for the occupied phase, not handover later.

In London, scrutiny increases due to high-density access constraints, mixed tenure and construction/occupation interface risk.

2. When Partial Gateway 3 Approval Is (and Isn’t) Realistic

Partial Gateway 3 approval can be possible where the occupied zone is:

• Physically separable (secure separation, independent access/egress)
• Functionally independent (life safety systems do not rely on unfinished zones)
• Operationally protected (construction activities cannot compromise residents)

Common London examples where partial approval may be possible:

• Podium complete / tower still ongoing (or vice versa)
• Multi-core arrangements with independent escape and systems
• Multiple blocks where one is complete and fully isolated

Where partial approval often fails:

• Shared lobbies, shared risers, shared smoke control strategy
• Construction works above/over occupied zones
• Temporary barriers used as fire separation

3. The Most Common BSR Refusal Reasons (London HRBs)

Based on typical early-occupation risks, refusals usually come down to:

Fire Strategy Not Phase-Specific

• Failure: One fire strategy used for both construction ongoing and occupation.
• BSR Expectation: A phase-specific fire strategy showing how residents remain safe while construction continues.

 

Incomplete Commissioning of Life Safety Systems

• Failure: Systems installed but not fully commissioned, tested or evidenced.
• BSR Expectation: Full proof of operational performance for the occupied area.

 

Golden Thread Not Live for the Occupied Phase

• Failure: Data is incomplete, scattered or not owned.
• BSR Expectation: Golden Thread information is complete and auditable for what is being occupied now.

 

Unsafe Construction / Occupation Interface

• Failure: Oversailing cranes, shared access routes, noisy/high-vibration works near residents without robust controls.
• BSR Expectation: A documented plan proving construction does not compromise residents’ safety.

 

London-Specific Constraints Ignored

• Failure: Fire appliance access assumed, logistics risk underestimated or TfL / neighbour interfaces not integrated.
• BSR Expectation: London realities clearly addressed, not generic UK assumptions.

4. 2026 Phased Occupation Compliance Checklist

Use this checklist to pre-validate a partial Gateway 3 application:

Fire & Life Safety Systems
✔ Phase-specific fire strategy is issued and internally validated.
✔ Fire detection/alarm, smoke control, emergency lighting and signage are fully commissioned for occupied areas.
✔ Evacuation approach for the occupied phase is confirmed (including management arrangements).

Separation & Access
✔ Occupied and construction zones are securely separated (not temporary tape and hope).
✔ Independent escape routes are available for residents.
✔ Fire appliance access for the occupied phase is confirmed and viable in real London conditions.

Golden Thread
✔ Safety information for the occupied area is complete, accurate, and accessible.
✔ Ownership is assigned (who updates what, when, and how).
✔ Handover materials reflect the reality of the occupied phase, not the final building.

Construction Interface Controls
✔ Construction logistics do not compromise resident safety (hoists, cranes, oversailing risk, dust, vibration).
✔ A live interface management plan exists, with monitoring and escalation procedures.
✔ Resident communication procedures are defined and enforceable.

London Constraints
✔ Zone 1 logistics constraints are accounted for (delivery windows, access, emergency routes).
✔ TfL / neighbour interfaces are reviewed and controlled.
✔ Mixed tenure operational responsibilities are clearly separated and documented.

 

At Gateway 3, BSR will validate that life-safety systems are commissioned, Golden Thread information is live for occupied phases,and interfaces between occupied and construction zones are safely managed. — this lines up with gov guidance.

5. Programme Implications for London Projects

 
Phased occupation is often introduced to protect programme, but if it is not designed as a standalone safety case, it creates the opposite outcome:

• Partial Gateway 3 refusal becomes a hard stop to occupation
• Rework and resubmission can add months, not weeks
• Commercial exposure increases (handover delays, liquidated damages, reputational risk)

 

For 2026 London HRBs, phased occupation must be treated as a regulated operational phase, not a programme workaround.

 

How Phased Occupation and Early Gateway Decisions Connect Across London’s 2026 Compliance Landscape

 

The phased occupation and partial Gateway 3 approval process for London Higher-Risk Buildings (HRBs) is not an isolated stage; it reflects a broader regulatory discipline taking shape across 2026. It intersects directly with the strengthened expectations for how applications are prepared and reviewed under the Building Safety Regulator, from the transfer of building control functions to the BSR through to the enhanced evidential requirements seen at Gateway 2 and in subsequent compliance milestones. 

 

This progression runs alongside changes to how the Single Construction Regulator assesses product liability, and sits within the greater emphasis on competence standards for Principal Designers whose role is critical in sequencing design, fire strategy and occupation planning. Evolving fire safety requirements, including second staircases and integrated evacuation strategies, also feed into how phased occupation is evaluated. 

 

At the same time, the regulatory emphasis on remediation delivery timelines and pace of action for existing buildings underlines the broader shift toward demonstrable progress over intention. When viewed together, these developments form a connected compliance environment where clarity on responsibility, programme certainty and evidence preparedness is essential across every stage of a London HRB project cycle.

 

image: constructionmagazine.uk

Expert Verification & Authorship: Mihai Chelmus Founder of London Construction Magazine | Construction Testing & Investigation Specialist | 15+ years in construction, 10+ years delivering projects in London. Writing practical guidance on regulation, compliance and real on-site delivery reality.