Completion Certificates and Gateway 3: Where London Projects Are Failing

Status 2026 Regulatory Reality Check
Regulator Building Safety Regulator (BSR)
Applicability London Higher-Risk Buildings (HRBs) – Completion, Handover & Occupation
Compliance Window Active (Gateway 3 Determinative)
 
In 2026 London HRBs, completion certificates are no longer administrative paperwork — they are a regulatory verdict.

Gateway 3 is where many London projects are discovering that good intentions, partial sign-offs and late-stage evidence assembly are not enough. The Building Safety Regulator (BSR) is treating completion as a life-safety decision, and completion certificates are being withheld where evidence does not demonstrate that the building has been delivered in accordance with the approved design and controlled through construction.

For projects that transitioned into the BSR regime, the transfer of building control functions to the BSR represents a hard reset. Historic assumptions about what “completion” looks like no longer apply.

This is not theoretical. Across London HRBs, projects are failing at Gateway 3 not because the building is unsafe, but because teams cannot prove it has been built safely.

1. What Gateway 3 actually tests in 2026

Gateway 3 is not a repeat of Gateway 2. It is not a design review. It is an evidence-based confirmation that:
  • The building has been constructed in accordance with the approved Gateway 2 design.
  • Safety-critical elements (fire and structure) perform as intended.
  • Change has been controlled, recorded and justified.
  • The Golden Thread is complete, coherent and auditable.

Where Gateway 2 tests intent, Gateway 3 tests delivery discipline. The BSR is asking a simple question: can an independent party reconstruct how this building was built and be satisfied it is safe?

2. Where London projects are failing at completion

The most common Gateway 3 failures seen on London HRBs in 2025–2026 fall into a small number of repeating patterns.

Incomplete or fragmented evidence
  • Fire stopping records missing, inconsistent or not linked to locations.
  • Façade installation evidence not aligned with the approved system.
  • Inspection records existing, but not traceable to specific safety-critical elements.

This often links back to weak construction governance. If evidence capture was not embedded into delivery, it cannot be reconstructed at the end. That is why Construction Control Plans are now central to Gateway 3 success.

Uncontrolled change between Gateway 2 and completion
  • Late substitutions justified commercially but not assessed for safety impact.
  • Design changes implemented on site without formal Gateway alignment.
  • Temporary measures treated as permanent solutions.

This is particularly acute around façade systems, where fire performance, installation quality and liability exposure converge. If the as-built façade cannot be evidenced as the approved façade, Gateway 3 confidence collapses.

Structural uncertainty left unresolved
  • Legacy structures not fully verified where loads or fixings changed.
  • Late strengthening works with incomplete test or inspection records.
  • Temporary works or sequencing assumptions not clearly closed out.

These failures often originate earlier in the project, where investigation evidence was insufficient. This directly connects to structural investigation expectations for legacy concrete frames.

3. Completion certificates: why “almost complete” no longer works

Historically, completion certificates could be issued with caveats, conditions or outstanding items. Under the HRB regime, this flexibility has narrowed sharply.

For London HRBs, completion certification now depends on whether life-safety systems are demonstrably complete, verified and documented. This includes:
  • Fire strategy implementation and commissioning.
  • Façade fire performance and installation verification.
  • Structural stability under permanent and foreseeable conditions.
  • Operational safety arrangements where occupation is intended.

If any of these elements rely on temporary assumptions, incomplete evidence or future works, the BSR is increasingly unwilling to allow completion to proceed.

4. Phased occupation: a common London pressure point

Many London projects seek partial handover to protect cash flow or programme. In 2026, this only works where the completion strategy has been designed around phased occupation and partial Gateway 3 approval from the outset.

Failures typically occur where:
  • Separation between occupied and construction zones is inadequately evidenced.
  • Life-safety systems are not fully commissioned for the occupied phase.
  • Control plans do not extend into the occupation interface.

Gateway 3 does not assess intent to make it safe later. It assesses whether the occupied part of the building is safe now.

5. The role of dutyholders at completion

Gateway 3 has sharpened focus on dutyholder accountability. Completion evidence is now one of the clearest indicators of whether dutyholders have exercised effective oversight throughout construction.

This is where competence expectations for Principal Designers and Principal Contractors become visible. Weak completion evidence is increasingly interpreted as a governance failure, not just a documentation issue.

6. A practical Gateway 3 readiness checklist (London HRBs)

Evidence completeness
✔ Fire stopping, façade and structural records are complete, traceable and location-specific.
✔ Inspection and test plans are closed out with signatures and dates.
✔ Nonconformances are resolved, re-checked and documented.

Change control
✔ All changes since Gateway 2 are logged, justified and approved.
✔ No safety-critical substitutions remain “temporary”.
✔ As-built information matches what is being certified.

Occupation interface
✔ Occupied areas are clearly defined and separated.
✔ Life-safety systems for the occupied phase are fully commissioned.
✔ Control plans extend into early occupation if applicable.

Golden Thread
✔ Evidence is structured, accessible and auditable.
✔ Decisions and sign-offs are attributable to named dutyholders.

Key takeaway

In 2026 London HRBs, Gateway 3 is where projects either demonstrate control or expose drift. Completion certificates are no longer a formality — they are a test of whether safety has been designed, built, verified and governed without compromise. Projects that succeed treat completion as a process that starts at Gateway 2, not a scramble at the end.

image: constructionmagazine.uk
Mihai Chelmus, founder of London Construction Magazine
Expert Verification & Authorship:
Founder of London Construction Magazine | Construction Testing & Investigation Specialist | 15+ years in construction, 10+ years delivering projects in London.
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